Local oscillator synchronization for coherent phased-array system

ABSTRACT

Aspects of the subject disclosure may include, for example, generating multiple digital reference pulses synchronously to a master oscillator, selectively switching the multiple digital reference pulses, and providing the switched pulses to multiple radio modules operating within a millimeter wave spectrum. For each radio module, counting cycles of an adjustable LO output signal occurring between consecutive pulses of the switched digital reference pulses, determining a difference between the count value and a reference value, and adjusting the adjustable LO according to the difference. A resulting corrected LO signal is synchronized to the master oscillator. Other embodiments are disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/102,666 filed on Nov. 24, 2020. The contents of each of the foregoingis/are hereby incorporated by reference into this application as if setforth herein in full.

GOVERNMENT LICENSE RIGHTS

This invention was made with government support under ECCS1731056awarded by the National Science Foundation. The government has certainrights in the invention.

FIELD OF THE DISCLOSURE

The subject disclosure relates to local oscillator synchronization forcoherent phased-array system.

BACKGROUND

The development of new wireless communications technologies hastraditionally been driven by a desire for higher data rates. Forexample, in commercial cellular applications, rapid increases in anumber of end-users and complexity of mobile applications of recentdecades have demanded a wireless communications solution that provideslow latency while achieving high instantaneous data rates in acomplicated physical environment with an unknown (a priori) number ofusers with unknown locations.

One solution to increase data rates includes moving to higher carrierfrequencies, e.g., including millimeter wave frequencies operating atK-band and above, in which traditional narrowband designs lead to highabsolute operating bandwidths. However, any move to such extremefrequencies does not come without cost. One such approach, termed 5G NewRadio (NR) marks a paradigm shift from omnidirectional to directivecommunications as higher-gain antennas are required to maintain aconstant-power link as the carrier frequency increases. Suchrequirements of high gain are a consequence of the Friis equation, whichstates that, for given antenna gain on transmit and receive, the receivepower is inversely proportional to the square of the operatingfrequency. The current solution to this spatially-multiplexed paradigmis a phased array.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the accompanying drawings, which are notnecessarily drawn to scale, and wherein:

FIG. 1 is a block diagram illustrating an exemplary, non-limitingembodiment of a communications network in accordance with variousaspects described herein.

FIG. 2A is a block diagram illustrating an example, non-limitingembodiment of a MIMO communication system functioning within thecommunication network of FIG. 1 in accordance with various aspectsdescribed herein.

FIG. 2B is a block diagram illustrating an example, non-limitingembodiment of a MIMO radio functioning within the communication networkof FIG. 1 and the MIMO communication system of FIG. 2A in accordancewith various aspects described herein.

FIG. 2C is a block diagram illustrating an example, non-limitingembodiment of a MIMO radio module functioning within the communicationnetwork of FIG. 1 and the MIMO communication system of FIG. 2A inaccordance with various aspects described herein.

FIG. 2D is planar view of an example, non-limiting embodiment of a MIMOradio module functioning within the communication network of FIG. 1 andthe MIMO communication system of FIG. 2A in accordance with variousaspects described herein.

FIG. 2E is a block diagram illustrating an example, non-limitingembodiment of a radio system including an antenna array functioningwithin the communication network of FIG. 1 and the MIMO communicationsystem of FIG. 2A.

FIG. 2F is a block diagram illustrating an example, non-limitingembodiment of a distributed, coherent LO system functioning with thecommunication network of FIG. 1, the MIMO communication system of FIG.2A, and the radio system of FIG. 2E in accordance with various aspectsdescribed herein.

FIG. 2G depicts a graphical representation of LO synchronization signalsaccording LO correction system functioning with the communicationnetwork of FIG. 1, the MIMO communication system of FIG. 2A, the radiosystem of FIG. 2E, and the distributed, coherent LO system of FIG. 2F inaccordance with various aspects described herein.

FIG. 2H is a block diagram illustrating an example, non-limitingembodiment of an LO correction system functioning with the communicationnetwork of FIG. 1, the MIMO communication system of FIG. 2A, the radiosystem of FIG. 2E, and the distributed, coherent LO system of FIG. 2F inaccordance with various aspects described herein.

FIG. 2I depicts an illustrative embodiment of a process that establishessynchronization of large numbers of LOs operating within a millimeterwave system in accordance with various aspects described herein.

FIG. 3 is a block diagram illustrating an example, non-limitingembodiment of a virtualized communication network in accordance withvarious aspects described herein.

FIG. 4 is a block diagram of an example, non-limiting embodiment of acomputing environment in accordance with various aspects describedherein.

FIG. 5 is a block diagram of an example, non-limiting embodiment of amobile network platform in accordance with various aspects describedherein.

FIG. 6 is a block diagram of an example, non-limiting embodiment of acommunication device in accordance with various aspects describedherein.

DETAILED DESCRIPTION

The subject disclosure describes, among other things, illustrativeembodiments for wireless communications systems in general, and tonext-generation wireless communications systems with high-dimensional,low-resolution architectures for power-efficient wireless communicationsin particular. Other embodiments are described in the subjectdisclosure.

One or more aspects of the subject disclosure include a system havingmultiple radio modules adapted to operate in a millimeter wave spectrum,a master oscillator adapted to provide a radio frequency (RF) reference,and a digital pulse generator in communication with the masteroscillator and adapted to provide a group of digital reference pulsessynchronously according to the RF reference. A pulse repetition rate ofa digital reference pulse is substantially less than a frequency of theRF reference. The system also includes a switch in communication withthe digital pulse generator and adapted to selectively provide aswitched digital reference pulse of the plurality of digital referencepulses to the multiple radio modules. Each of the radio modules includesan adjustable local oscillator (LO) adapted to provide an LO outputsignal and a counter in communication with the switch and the adjustableLO. The counter is adapted to count cycles of the LO output signaloccurring between consecutive pulses of the switched digital referencepulse to obtain a count value. Each of the radio modules also includesan error detector in communication with the counter and the adjustableLO. The error detector is adapted to generate an error signal accordingto a difference between the count value and a reference value, whereinthe adjustable LO is adapted to provide a corrected LO signal responsiveto the error signal. The corrected LO signal is synchronized to themaster oscillator.

One or more aspects of the subject disclosure include a process thatincludes generating multiple digital reference pulses synchronized to anRF reference of a master oscillator. A pulse repetition rate of adigital reference pulse of the multiple digital reference pulses issubstantially less than a frequency of the RF reference. The multipledigital reference pulses are selectively switched to obtain multipleswitched digital reference pulses. The multiple switched digitalreference pulses are provided to multiple radio modules operating withina millimeter wave spectrum, wherein each of the radio modules includesan adjustable LO. The process further includes counting cycles of an LOoutput signal of the adjustable LO occurring between consecutive pulsesof the switched digital reference pulses to obtain a count value. Adifference is determined between the count value and a reference value,and the adjustable LO is adjusted according to the difference to obtaina corrected LO signal, wherein the corrected LO signal is synchronizedto the master oscillator.

One or more aspects of the subject disclosure include a multiple inputmultiple output (MIMO) radio, which includes multiple radio modulesadapted to operate in a millimeter wave spectrum, a master oscillatoradapted to provide an RF reference, and a digital pulse generator incommunication with the master oscillator. The digital pulse generator isadapted to provide multiple digital reference pulses based on the RFreference. The MIMO radio also includes a switch in communication withthe digital pulse generator and adapted to provide respective digitalreference pulses to each of the radio modules. Each radio moduleincludes a controllable LO adapted to provide an LO output signal and acounter in communication with the switch and the controllable LO,wherein the counter is adapted to count according to the LO outputsignal and the respective digital reference pulses to obtain a countvalue. Each radio module further includes a difference detector incommunication with the counter and the controllable LO, wherein thedifference detector is adapted to determine a difference between thecount value and a reference value. The controllable LO is adapted toprovide a corrected LO signal responsive to the difference, wherein thecorrected LO signal is coherent with other radio modules of the multipleradio modules.

High-resolution, high peak-to-average-power communication modulationformats such as OFDM (LTE) have traditionally required both the basestation (BS) and user equipment (BE) to maintain a high degree oflinearity. An imposition of such linearity requirements, however, limitsefficiencies and indirectly a maximum practical power output of atransmitter. Such linearity requirements have also necessitated anymixing circuits as may be used in either transmit or receive operation,to incorporate high-powered local oscillators. Linearity in gain stagesand low noise amplifiers is also paramount. This ultimately results in asystem with inefficient amplification and high-power requirements. In amassive MIMO deployment scenario, the power consumption of thetransceiver system scales roughly linearly with the number oftransmitter/receiver (Tx/Rx) elements, which can prove impractical forsystems employing high peak-to-average power ratio modulations requiringtraditional highly-linear design. This downside is further compounded inthe phased array system, which employs high-resolution complex amplitudecontrol, typically in the RF chain, to achieve beamforming at theexpense of power consumption and efficiency.

The example embodiments disclosed herein use low-resolution, e.g.,single-bit or perhaps a few bit, transmitters and/or receivers and/ortransceivers as means of relaxing the linearity and power requirementsof next-generation wireless communications. An easily replicable, lowpower, low cost, RF-in, bits-out one-bit receiver cell forms the basicbuilding block of a nonlinear MIMO cellular system. This transceiverarchitecture enables simple beamforming in the digital domain.

The devices, systems and techniques disclosed herein may be applicableto any wireless communications application, but are particularlysuitable for high-frequency cellular communications operating atfrequencies within K-band and above K-band, at which the propagationcharacteristics of microwave and millimeter-wave signals typically relyon high-gain antennas and encourage spatial multiplexing. The inherentspectral inefficiency of low-resolution modulation schemes becomes lessof a concern when fewer end users are sharing identical space-bandwidth.Additionally, as the carrier frequency increases, solid-state amplifiersare less able to provide gain due to transistor parasitics, which resultin a finite maximum operating frequency that further increasescomplexity and power consumption for a given output power. At least onecounterintuitive technique disclosed herein is to operate one or more RFsignal processing devices, such as LOs, signal combiners, square lawdetectors and/or transistor amplifiers in their most efficient nonlinearregime to reduce power consumption.

The illustrative examples provided herein include ultra-low-power,low-complexity, scalable radio receivers, such as the example MIMO radiocells. These radio cells exploit nonlinearities in their devices and/orcircuits to obtain very low power consumption and ease of fabrication ina variety of technologies for wide bandwidths and at very high carrierfrequencies. Such radio cell may include a receiver or a transmitter orreceiver and transmitter. In at least some embodiments, the radio cellis configured to demodulate or to modulate or to modulate and demodulatea single bit, or perhaps a few bits, e.g., two bits per symbol. At leastsome of the illustrative example radio cells disclosed herein includeenergy detectors, such as envelope detectors and/or square law detectorsthat utilize detection directly from a received RF carrier, withoutrequiring down-conversion and/or the use of mixers and/or localoscillators, such as U.S. patent application Ser. No. 16/988,103,entitled “Ultra-Low-Power Millimeter-Wave to Baseband Receiver Modulefor Scalable Massive MIMO,” which is incorporated herein by reference inits entirety. Other illustrative example radio cells disclosed hereininclude signal combiners adapted to convert phase modulated signals,e.g., PSK signals, to amplitude modulated signals, e.g., pulse amplitudemodulated signals suitable for detection by energy detectors, such asthe aforementioned envelope detectors and/or square law detectors, asdisclosed in U.S. patent application Ser. No. 17/103,152, entitled“Low-Resolution, Low-Power, Radio Frequency Receiver,” Attorney DocketNo. 2020-0176_7785-2315A, which is also incorporated herein by referencein its entirety. Beneficially, such single-bit receivers and/ortransmitters and/or transceivers relax linearity and power requirementsof next-generation wireless communications. The simple radio cellsdisclosed herein are low power, low cost, easily replicable RF-in,bits-out, low-bit receivers, e.g., one-bit receivers, that form basicbuilding block of a nonlinear MIMO cellular system. It is understoodthat, without limitation, such transceiver architectures enable simplebeamforming in the digital domain.

Referring now to FIG. 1, a block diagram is shown illustrating anexample, non-limiting embodiment of a communications network 100 inaccordance with various aspects described herein. For example,communications network 100 can facilitate in whole or in part receiving,by a first radio module at a first location, a wireless MIMO signal, toobtain a first received RF signal. Alternatively or in addition, thecommunications network 100 may facilitate in whole or in parttransmitting, by the first radio module at a first location, a wirelessMIMO signal, to obtain a first transmitted RF signal.

The MIMO signal of a first received RF signal may include informationoriginating at a remote MIMO transmitter and conveyed via a wirelesschannel. In at least some embodiments, e.g., for on-off-keying (OOK)modulation, an envelope of the first received RF signal may be detectedby the first radio module without requiring a local oscillator, toobtain a first detected baseband signal. For phase modulated received RFsignals, e.g., according to phase-shift keying (PSK), including binaryPSK (BPSk), differential PSK (DPSK), and the like, a local oscillatormay be mixed with the first received RF signal to obtain a basebandsignal that may be detected using a square law detector, e.g., anenvelope detector. The first detected baseband signal is compared to areference value to obtain a first digital signal that is provided to adigital processor. The digital processor also obtains a second digitalsignal from a second radio module receiving the wireless MIMO signal ata second location and determines an estimate of the informationoriginating at the remote MIMO transmitter according to the first andsecond digital signals. In particular, a communications network 125 ispresented for providing broadband access 110 to a plurality of dataterminals 114 via access terminal 112, wireless access 120 to aplurality of mobile devices 124 and vehicle 126 via base station oraccess point 122, voice access 130 to a plurality of telephony devices134, via switching device 132 and/or media access 140 to a plurality ofaudio/video display devices 144 via media terminal 142. In addition,communication network 125 is coupled to one or more content sources 175of audio, video, graphics, text, and/or other media. While broadbandaccess 110, wireless access 120, voice access 130 and media access 140are shown separately, one or more of these forms of access can becombined to provide multiple access services to a single client device(e.g., mobile devices 124 can receive media content via media terminal142, data terminal 114 can be provided voice access via switching device132, and so on).

The communications network 125 includes a plurality of network elements(NE) 150, 152, 154, 156, etc., for facilitating the broadband access110, wireless access 120, voice access 130, media access 140 and/or thedistribution of content from content sources 175. The communicationsnetwork 125 can include a circuit switched or packet switched network, avoice over Internet protocol (VoIP) network, Internet protocol (IP)network, a cable network, a passive or active optical network, a 4G, 5G,or higher generation wireless access network, WIMAX network,UltraWideband network, personal area network or other wireless accessnetwork, a broadcast satellite network and/or other communicationsnetwork.

In at least some embodiments, the base station or access point 122 maybe adapted to include a low-power radio, such as a low-power MIMO radio182, having a PSK transmitter, and/or an PSK receiver and/or an PSKtransceiver according to the low-power, low-complexity radios andrelated devices disclosed herein. Likewise, in at least someembodiments, the mobile devices 124 and vehicle 126 may be adapted toinclude a low-power radio, such as a low-power MIMO radio, 183 a, 183 b,183 c, generally 183, having a PSK transmitter, and/or an PSK receiverand/or an PSK transceiver according to the low-power, low-complexityradios and related devices disclosed herein.

In various embodiments, the access terminal 112 can include a digitalsubscriber line access multiplexer (DSLAM), cable modem terminationsystem (CMTS), optical line terminal (OLT) and/or other access terminal.The data terminals 114 can include personal computers, laptop computers,netbook computers, tablets or other computing devices along with digitalsubscriber line (DSL) modems, data over coax service interfacespecification (DOCSIS) modems or other cable modems, a wireless modemsuch as a 4G, 5G, or higher generation modem, an optical modem and/orother access devices.

In various embodiments, the base station or access point 122 can includea 4G, 5G, or higher generation base station, an access point thatoperates via an 802.11 standard such as 802.11n, 802.11ac or otherwireless access terminal. The mobile devices 124 can include mobilephones, e-readers, tablets, phablets, wireless modems, and/or othermobile computing devices.

In various embodiments, the switching device 132 can include a privatebranch exchange or central office switch, a media services gateway, VoIPgateway or other gateway device and/or other switching device. Thetelephony devices 134 can include traditional telephones (with orwithout a terminal adapter), VoIP telephones and/or other telephonydevices.

In various embodiments, the media terminal 142 can include a cablehead-end or other TV head-end, a satellite receiver, gateway or othermedia terminal 142. The display devices 144 can include televisions withor without a set top box, personal computers and/or other displaydevices.

In various embodiments, the content sources 175 include broadcasttelevision and radio sources, video on demand platforms and streamingvideo and audio services platforms, one or more content data networks,data servers, web servers and other content servers, and/or othersources of media.

In various embodiments, the communications network 125 can includewired, optical and/or wireless links and the network elements 150, 152,154, 156, etc., can include service switching points, signal transferpoints, service control points, network gateways, media distributionhubs, servers, firewalls, routers, edge devices, switches and othernetwork nodes for routing and controlling communications traffic overwired, optical and wireless links as part of the Internet and otherpublic networks as well as one or more private networks, for managingsubscriber access, for billing and network management and for supportingother network functions.

FIG. 2A is a block diagram illustrating an example, non-limitingembodiment of a MIMO communication system 200 functioning within thecommunication network of FIG. 1 in accordance with various aspectsdescribed herein. According to the illustrative example, the MIMOcommunication system 200 includes a transmitter portion 201 and anonlinear receiver portion 202. The transmitter portion 201 includes anM-bit digital beamforming system 203 in communication with M antennas orradiating elements 204 a, 204 b, . . . , 204M, generally 204. Thereceiver portion 202 includes N antennas 205 a, 205 b, . . . , 205N,generally 205. Each of the antennas 205 is coupled to a respective radioreceiver 206 a, 206 b, . . . , 206N, generally 206, which are coupled,in turn, to an N-bit digital receiver processing system 207. Wirelesscommunication signals propagate between the transmitter portion 201 andthe receiver portion 202 via a wireless channel 208.

The example nonlinear receiver portion 202 uses an RF-in, bits-outapproach that is well-suited for a low-cost, low-power solution to thescaling problem that arises in massive MIMO. The receiver portion 202may include one or more highly efficient antenna-coupled nonlinearamplifiers and one or more low-power RF signal processing elements thatmay include detector elements. Low-power RF signal processing elementsmay include, without limitation, power dividing/summing devices, such asWilkinson power dividers, local oscillators operating at low powerand/or nonlinear rectifying elements, e.g., diodes, that facilitate adirect-to-baseband demodulator, sometimes referred to as anon-off-keying (OOK) demodulator. The low-powered LO, when applied to amixer, is sometimes referred to as a starved mixer. By combining areceived PSK-modulated RF signal with an LO signal operating at the RFcarrier, the PSK signal can be converted to one or more PAM signals,e.g., I and/or I and Q PAM signals. The resulting PAM signals areprovided to a detector element to obtain baseband output signals. In atleast some embodiments, baseband signals can be digitized, e.g., using acomparator that may be configured with a fixed and/or an adjustablethreshold upon which comparisons are determined.

It is understood that in at least some embodiments baseband processingmay occur prior to digitization. For example, one or more of gain,filtering and/or attenuation may be applied to one or more of thebaseband signals. Filtering may include passive filtering and/or activefiltering. In a massive MIMO deployment, the digital outputs of eachnonlinear receiver chain may be further processed in a digital domain toachieve an enhanced, and ideally a maximum channel capacity. In afull-rank channel, capacity saturates with the number of transmitters,assuming more receivers than transmitters, one-bit-per-transmitter asthe signal to noise ratio increases. Consequently, more than onebit-per-channel use may be achieved as a number of transmitter andreceiver chains increase; this is exemplified by the trivial case of Msingle-input-single-output (SISO) channels with one transmitter and onereceiver, which can achieve M bits-per-channel use.

Although the illustrative examples disclosed herein refer to envelopedetection or OOK, it is understood that other communication techniquesmay be used. For example, information may be impressed upon atransmitted RF according to a different modulation, such as phasemodulations, e.g., PSK and/or differential PSK (DPSK). In suchapplications, the receivers disclosed herein may be adapted as disclosedherein to perform detection to obtain baseband signals according to thetype of modulation applied to the RF signal. Such applications may usewell established techniques, such as DPSK, energy thresholding or acombination thereof.

FIG. 2B is a block diagram illustrating an example, non-limitingembodiment of a MIMO radio module or cell 210 functioning within thecommunication network of FIG. 1 and the MIMO communication system ofFIG. 2A in accordance with various aspects described herein. The exampleMIMO radio cell 210 includes at least one antenna 211, an RF signalprocessing/detection module 215, a baseband amplifier 216, and an ADC,e.g., a 1-bit ADC 217. In at least some embodiments, the MIMO cell 210includes one or more of an antenna coupler 213 and an RF amplifier 214(both shown in phantom). It is understood that some embodiments may notrequire a separate antenna coupler 213. Alternatively or in addition, atleast some embodiments may not require an amplifier 214. Depending onthe desired degree of baseband analog processing, some embodiments maynot require the baseband amplifier 216. For example, a minimal MIMOradio module may include an antenna 211, an RF signalprocessing/detection module 215 and a 1-bit ADC, without necessarilyrequiring one or more of the antenna coupler 213 or the RF amplifier 214and baseband amplifier 216.

In at least some embodiments, the RF signal processing/detection module215 receives an LO signal to facilitate detection of PSK and DPSKsignals. In some embodiments, the MIMO radio cell 210 includes an LO 209(shown in phantom) that provides an LO signal operating at a carrierwave frequency of the received RF signals. The LO 209 is operated in alow-power configuration, resulting in a so-called “starved” mixer, inwhich the LO signal level biases a nonlinear element such as a diodewell below the threshold voltage/built-in potential, e.g., a diode, of amixer and/or a signal detector to which the LO signal may be applied. Insome embodiments, the LO 209 is integral to the RF signalprocessing/detection module 215. Alternatively or in addition, the LO209 may be separate from the RF signal processing/detection module 215,but integral to the MIMO radio cell 210. It is envisioned that in atleast some embodiments, a single LO module 209 may supply an LO signalto more than one such RF signal processing/detection modules 215 and/orto more than one MIMO radio cells 210. In some embodiments, the LO 209may be phase locked to the received RF signal, e.g., using feedbackcontrol, such as a phase locked loop (PLL). Alternatively or inaddition, the LO 209 may operate without necessarily being phase lockedto the RF signal, e.g., without an application of feedback control tofurther simplify the radio architecture.

Due to the very large bandwidths available in millimeter wave spectrum,digital-to-analog converters (DAC) and ADCs must work at very highsampling rates. Since their power consumption scales approximatelylinearly in the sampling rate and exponentially in the number of bitsper sample, only very few data converters are employed instate-of-the-art systems and a base station with hundreds of antennaelements may only have a handful of data converters. Unlike fully analogbeamforming systems, where phase and amplitude can individually becontrolled per antenna element, limiting the number of data converterscompromises robustness and mobility rendering millimeter wave spectrumless attractive for new use cases such as ultra-reliable low latencycommunications (URLLC).

Such simplified, or minimal complexity MIMO radio cells 210 offerseveral advantages. For example, a minimally complex module or cell mayoccupy a relatively small area of a MIMO receiver portion 202. Spacesavings may be advantageous for mobile device applications, e.g., for amobile phone, a tablet, a PC, for appliance applications, such as smartTVs, and/or Internet of Things (IoT) devices, e.g., home appliances,printers, security system components, surveillance cameras, residentialcontrollers, personal assistants, cloud-based voice service appliances,and the like. In the illustrative example, the dipole antenna 218 has amaximum dimension determined by its length, L. The example MIMO radiocell 210 occupies an area defined by the dipole antenna length L, and amodule width, W. In at least some embodiments, the width W is less thanthe length L, i.e., W<L, such that an area occupied by the module isless than a square of the maximum antenna dimension, i.e., A=L×W≤L².

Dimensions of an antenna, such as the example dipole antenna 218, whichhappens to be a bowtie type of dipole antenna adapted to provide arelatively wide operational bandwidth, may be determined from an antennacalculator. For example, a length L may be determined according to:L=0.75λ. Likewise, a width w may be determined according to w=0.25λ. Forexample, the MIMO radio cell 210 configured to operate in the Ka band,having a frequency between about 26.5-40 GHz, and a correspondingfree-space wavelength between about 11.1 and 7.5 mm. Assuming operationat a center frequency of about 33 GHz, the free-space wavelength isabout 9.1 mm, may have a length L≈6.8 mm and a width w≈2.3 mm.Accordingly, an area occupied by a Ka band MIMO radio may be less thanabout 7 mm×7 mm≈50 mm².

Other advantages of simplified, or minimal complexity MIMO radio cells210 include relatively low power requirements and relatively low thermalload. According to the examples disclosed herein, the MIMO radio cells210 use simple energy detectors, such as envelope detectors, or squarelaw detectors. Such simple detectors may operate on the received RFsignal directly without requiring any local operator and/or mixing toobtain an intermediate frequency between RF and baseband, as would betypical for millimeter wave digital communication systems. Rather thesimple detectors may obtain a baseband signal directly from the RFsignal according to an envelope of the RF signal and/or from a PSKand/or DPSK type receiver employing a low powered LO in combination witha nonlinear device providing a mixing of the RF and the LO. Moreover,the low-resolution, e.g., single-bit, ADC may be operated in a nonlinearregion, e.g., using a simple comparator circuit, without requiringhigh-resolution, linear ADCs, as would be typical for millimeter wavedigital communication systems. Still further, should signalamplification be used, e.g., providing an LNA 214 between the antenna218 and the RF processing/detection module 215, the LNA 214 does notneed to be operated in a linear region. As the low-resolution ADCsolution relies upon a simple comparator circuit 217, linearity of thereceived signal does not need to be preserved. Accordingly, theamplifier, e.g., LNA 214, may be operated in a nonlinear region, e.g.,in saturation. As is true with operation of the low-power LO 209, it isunderstood that operation of an amplifier, e.g., LNA 214, without regardto preserving linearity, e.g., in saturation, may be accomplished asubstantially less power dissipation that would be required for linearoperation. Likewise, operating the minimal complexity MIMO radio cell210 requires relatively low power, certainly much less than traditionaldigital communication receivers operating in comparable wavelengths.Consumption of less power results in generation of less of a thermalload, e.g., according to component inefficiencies, power requirementsand/or circuital resistive losses.

Beneficially, the factors contributing to smaller, simpler and coolerMIMO receiver modules also reduce initial costs as well as operationalcosts, e.g., lower power consumption and cooling. The reduced modulesize and reduced thermal load further allows more MIMO receiver modulesto be used in the same space than would otherwise be possible withtraditional MIMO receivers employing higher-resolution ADCs, and/or LNAsoperating in their linear regions, digital receivers and/or detectorsemploying traditional LO-mixer combinations, e.g., not starved, butrather operating in a linear region. The reduced cost, thermal load andsize permit larger numbers to be used within the same footprint, whichis well adapted for massively MIMO systems. It is envisioned thatmassively MIMO systems may employ scores, if not hundreds, or even moreMIMO receiver modules.

The example MIMO radio cell 210 includes a dipole antenna 218—in thisinstance, a bowtie antenna 218. It is understood that in general theantenna 211 may include a balanced structure, such as a dipole, anunbalanced structure, such as a monopole, and/or a patch. The antennamay be a resonant structure, such as the example dipole antenna 218,having a length L that approximates one-half of an operating wavelength(λ), i.e., L≈λ/2. Without limitation, the antenna 211 may include anelectric-field sensing element, a magnetic-field sensing element, or acombination of both an electric-field and a magnetic-field sensingelements. By way of non-limiting example, it is understood that antenna211 may include a wire structure, such as a dipole, a monopole, or aloop. It is understood that a loop antenna 211 may be configuredaccording to varying geometries, e.g., a circular loop, an ellipticalloop, a square loop, and a rectangular loop. A wire structure antenna211 may be free-standing, e.g., formed from a rigid conductor and/orformed on a substrate 219 and/or similar supporting structure. Theantenna 211 may be substantially omnidirectional, such as the exampledipole 218 structure. Alternatively or in addition, the antenna 211 mayoffer some directivity.

It is understood further that the antenna 211 may operate according to apreferred polarization, such as a linear polarization, a circularpolarization, or more generally, an elliptical polarization. By way ofexample, the dipole antenna 218 may be replaced with a crossed dipole,in which two dipole antennas are positioned in an orthogonal arrangementand coupled to a common antenna terminal 212 via a phase shiftingelement, e.g., a 90-degree phase shifter. Still other antenna 211 mayinclude antenna arrays, such as Yagi antenna arrays, log-periodicstructures, spiral antennas and the like.

The antenna coupler 213 is positioned between the antenna terminal 212and the RF processing/detection module 215. For embodiments, in which again element, such as the example LNA 214 is included, the antennacoupler 213 may be positioned between the antenna terminal 212 and theLNA 214. In at least some embodiments, the antennal coupler 213 ispositioned at the antenna terminal 212. The antenna coupler 213 mayinclude a matching network, such as a conjugate matching networkmatching a driving point impedance of the antenna 211 to acharacteristic impedance of a transmission line extending between theantenna coupler 213 and one or more of the gain element 214 and the RFprocessing/detection module 215.

Alternatively or in addition, the antenna coupler 213 includes a balun.The balun is adapted to facilitate a coupling of a balanced structure,such as the example dipole antenna 218 and an unbalanced structure, suchas an unbalanced transmission line. Baluns can facilitate operation of abalanced device, such as the example dipole antenna 218 by promoting asubstantially symmetric current distribution between each half of thedipole antenna 218. Baluns may include one or more of transmissionlines, lumped elements, e.g., capacitors and/or inductors, includingtransmission line elements, e.g., λ/4 transmission line segments, andthe like. In at least some embodiments, the balun structure may includea lossy element, such as a ferrite element and/or RF chokes adapted toabsorb and/or otherwise prevent propagation of unbalanced currents.

In at least some embodiments, the MIMO radio cell 210 includes one ormore filters. Filters may include, without limitation, high-passfilters, low-pass filters and band-pass filters. In at least someembodiments, filters may be analog filters, e.g., constructed accordingto lumped resistor and/or inductor and/or capacitor components.Alternatively or in addition, analog filters may utilize one or morewaveguide segments, such as waveguide lengths, shorted waveguide stubsand/or open waveguide stubs positioned at predetermined lengths along awaveguide, and the like. One or more filters may be provided, forexample, at one or more of the antenna terminal 212, the antenna coupler213, an input of the LNA 214, and output of the LNA, an input of the RFprocessing/detection module 215 and/or at the output of the RFprocessing/detection module 215, and/or the output of a basebandprocessing stage, such as the example baseband amplifier 216. In someembodiments the filters may be high-pass filters adapted to block DCcurrents. Alternatively or in addition, the filters may be low-passfilters adapted to pass baseband currents.

The RF processing/detection module 215 may include any device having anon-linear characteristic curve, e.g., a non-linear current-voltage(I-V) curve. Examples include, without limitation, a diode, atransistor, e.g., a transistor wired in a diode configuration. Inpractical applications, parasitic values of the detector may be selectedto ensure minimal signal degradation resulting from operation of thedetector device at the frequencies of operation, e.g., at the RF thecarrier frequency and/or the baseband frequency.

In some embodiments, the MIMO receive cell 210 may include a basebandamplifier 216 designed to amplify the baseband signal from the output ofan envelope detector of the RF processing/detection module 215 to asuitable voltage/current/power level as required by comparator ADC 217.The amplifier 216 may also act as an impedance-transforming buffer stagebetween the RF processing/detection module 215 and comparator 217.

The comparator may include any suitable device to provide a stablebinary output according to a comparison of an input baseband signal to areference value. For example, the reference value may be a referencevoltage. A value of the reference voltage may be selected to serve as adecision between a binary 1 or a binary 0. For example, if an expectedvoltage of a received baseband signal is expected to be 0 and 10microvolts, a threshold value may be selected as ½ the maximum value,i.e., about 5 microvolts. In at least some embodiments, the thresholdvoltage is determined according to a minimum signal level, e.g., asystem noise floor, in which a received voltage above a predeterminedvalue above the noise floor may represent a binary 1. In someembodiments, the threshold value is fixed. Alternatively or in addition,the threshold value may be variable, e.g., according to signalconditions, noise, conditions, a calibration value, and so on.

As an example, assume a simplified passive embodiment of receiver MIMO210 that omits amplifiers 214 and 216. Further assume that the system isimpedance matched and the noise seen at the comparator is solely due tothermal noise generated in the envelope detector. It is well-known thatthermal noise in passive systems exhibits a flat spectral power densityof −174 dBm/Hz. If the system bandwidth is 1 GHz, the correspondingnoise power is −84 dBm. Suppose that the input power to the system is−50 dBm (for signal symbol 1) and the aggregate loss from antenna 218,coupler and/or filter 213, amplifier 214, and RF processing/detectionmodule 215 is 20 dB. This corresponds to an output power ofapproximately −70 dBm at the input comparator 217. Since the SNR isrelatively high (14 dB), one-half the signal voltage at comparator 217will approximately lie halfway between the noise floor voltage andsignal on-state. From a voltage standpoint, halving the voltage reducespower by one-fourth, which corresponds to a threshold power of −76 dBm.Assuming a 50-Ohm input impedance, this corresponds to a thresholdvoltage of approximately 35 μV. In the event that the comparatorhardware 217 is unable to detect voltage differences this low, becauseof, e.g., built-in hysteresis, it will be of benefit to instate basebandamplifier 216 to accommodate lower input power operation. One potentialstrategy for adjusting the threshold is feedback based on individualdigital outputs, i.e., if the comparator 217 is outputting all binary1's, the comparator threshold may be set too low and should beincreased.

If a pre-amplifier at millimeter-wave is included, then the link budgetwould improve significantly due to the square-law device. That is, ifthe power incident upon the receive cell is −70 dBm and themillimeter-wave LNA gain is 30 dB, with a diode responsivity of 10 kV/Wthis corresponds to a 1 mV baseband output voltage. Even this is likelytoo low to pass along to a standard CMOS threshold detector which wouldhave noise and hysteresis. Therefore a baseband voltage amplifier withe.g., 10V/V gain might be used. The baseband amplifier would have highinput impedance (e.g., greater than the diode video resistance over thechannel bandwidth of −1 GHz, as an example). It would also haverelatively low output resistance in order to pass a multi-GHz signalacross the input capacitance of a CMOS threshold detector IC (perhaps500 ohms output resistance or less).

FIG. 2C is a block diagram illustrating an example, non-limitingembodiment of a MIMO radio module 220 functioning within thecommunication network of FIG. 1 and the MIMO communication system ofFIG. 2A in accordance with various aspects described herein. The exampleMIMO radio module 220 includes four RF signal processing/detectioncells, 222 a, 222 b, 222 c, 222 d, generally 222. It is understood thatother numbers of RF signal processing/detection cells 222 may be usedwithin a MIMO radio module 220, including numbers greater than and/orless than four. Such numbers may be selected based on one or more ofpower requirements, thermal loading, operating frequency range,manufacturability, size constraints, cost, complexity, reliability, andso on. Each of the RF signal processing/detection cells 222 is coupledto a respective interconnect or terminal 224 a, 224 b, 224 c, 224 d,generally 224, via a respective transmission line 223 a, 223 b, 223 c,223 d, generally 223. The terminals 224 may include an electricalinterconnect adapted for repeated connections and disconnections, e.g.,a connector, such as a coaxial connector, a push-pin connector, and thelike. Alternatively or in addition the terminals 224 may include morepermanent electrical interconnects, such as solder pads.

According to the illustrative example, a respective digital signaland/or digital values y1, y2, y3, y4 is available and/or otherwiseaccessible at each terminal 224 of the group of terminals 224. Thedigital signal and/or value y1, y2, y3, y4 may be equivalent to anoutput of the comparator 217 (FIG. 2B) of each cell 222. The digitalsignals/values y1, y2, y3, y4 are provided to a digital signal processor(not shown) for combination and/or digital processing. At least oneexample digital signal processor is the N-bit digital receiverprocessing system 207 (FIG. 2A).

The RF signal processing/detection cells 222 may be identical cells,e.g., according to the example MIMO radio cell 210 (FIG. 2B).Alternatively, the RF signal processing/detection cells 222 may differ,e.g., some RF signal processing/detection cells 222 adapted for oneportion of an RF spectrum, while other cells 222 are adapted for anotherportion of the RF spectrum. Alternatively or in addition, some RF signalprocessing/detection cells 222 may be adapted for one polarization,e.g., linear horizontal, while other RF signal processing/detectioncells 222 are adapted for another polarization, e.g., linear vertical.Some RF signal processing/detection cells 222 may be adapted to includeLNAs 214, while other RF signal processing/detection cells 222 may not.For example, those RF signal processing/detection cells 222 without LNAs214 may operate in a passive mode when signal conditions permit, e.g.,relative strong received signal levels, relatively low interferenceand/or favorable channel conditions. Other RF signalprocessing/detection cells 222 with the LNAs 214 may be selectivelyengaged and/or otherwise activated according to unfavorable signalconditions, e.g., relative weak received signal levels, relatively highinterference and/or unfavorable channel conditions. Such different cellsmay be arranged on the same MIMO radio module 220, e.g., interspersed,and/or arranged in groups.

It is envisioned that in at least some embodiments, all of the RF signalprocessing/detection cells 222 of a particular MIMO radio cell 210 maybe adapted for one type of RF signal modulation, e.g., OOK and/or PSKand/or DPSK, and the like. It is envisioned further that in at leastsome embodiments one or more different types of MIMO radio cells 210 maybe used within a common MIMO radio application. For example, a MIMOradio may include one or more MIMO radio cells 210 adapted for OOKmodulation and one or more other MIMO radio cells 210 adapted for PSKmodulation. Alternatively or in addition, a single MIMO radio cells 210may include one or more different types of RF signalprocessing/detection cell 222, e.g., with at least one RF signalprocessing/detection cell 222 adapted for PSK and/or DPSK modulation,and at least one other RF signal processing/detection cell adapted forOOK modulation. It can be appreciated that such mixed modeconfigurations can offer flexibility in operation and/or application. Asmaterial and/or fabrication costs are anticipated to be relatively lowin view of the simple, low-complexity architectures, and as dimensionsof any realizable modules amenable to compact systems, such mixed modeconstructions may be used despite there being any immediate need formixed mode operation. Namely, a mixed mode device may be deployed, butonly operated according to one of multiple available modes.

Alternatively or in addition different MIMO radio modules 220 may becombined within a common receiver portion 202 (FIG. 2A). For example, afirst group of MIMO radio modules 220 may include passive detectors,e.g., without LNAs 214, while a second group of MIMO radio modules 220may include active detectors, e.g., including LNAs 214. Otherparameters, such as antennas, matching networks and/or filters, whenprovided, may differ within the same MIMO radio module 220 and/oraccording to the different groups of MIMO radio modules.

In at least some embodiments, one or more of the cells 222 may includean active element, such as an LNA 214, and/or an LO 209 and/or acomparator 217 (FIG. 2B). In such instances, each of the cells 222 mayrequire electrical power, e.g., according to one or more voltage levels.It is envisioned that in at least some embodiments, the electricalpower, e.g., the one or more voltage levels may be provided by one ormore power supplies 225 provided at the MIMO radio module 220.Alternatively or in addition, one or more voltage levels may be providedby a separate power source, such as a stand-alone power supply. In suchconfigurations, the MIMO radio module 220 may include a powerinterconnect, e.g., a connector, adapted to interconnect to a remotepower source. Conductors, e.g., traces, may be provided from contacts ofa power connector to each of the cells 222. In at least someembodiments, a single LO 227 may supply an LO signal to one or more ofthe cells 222, as illustrated. It is understood that in at least someembodiments, the LO may be integral to the MIMO cell 220. In suchinstances, the LO may also obtain power from the power supply 225.Alternatively or in addition, the LO may be supplied separately from theMIMO cell 220.

According to the illustrative example, the MIMO radio cells 222,including antennas 211 (FIG. 2B), are spaced according to acenter-to-center distance d. Depending upon a size and/or shape of thecells, there may be a separate distance between adjacent cells, asshown. However, it is envisioned that in at least some embodiments, thecells 222 may be adjacent to each other, such that there is noseparation between adjacent cells 222. The cell spacing d may be uniformbetween all cells 222 of the module 220. Alternatively the cell spacingd may vary between at least some of the cells 222.

According to the illustrative example module, the cells 222 are arrangedin a one-dimensional fashion, e.g., along a common linear axis 226. Insome embodiments, the cells may be arranged in a two-dimensionalfashion, e.g., according to a 2-dimensional (2D) pattern. The 2D patternmay be a regular pattern, in which spacings between adjacent cells 222is uniform, e.g., constant in one or two dimensions. Example 2D pattersinclude, without limitation, a rectangular grid, a hexagonal close packgrid, and the like. Such 3D patterns are beneficial at least in thatthey permit a greater number of cells 222 to be provided within arelatively compact receiver portion 202. It is envisioned that in atleast some embodiments, the cells 222 may be arranged in athree-dimensional (3D) fashion, e.g., according to a conformal patternthat may conform to a 3D surface, such as a cube, a tetrahedron, aparallelepiped, a cone, or a curved surface, such as a spherical portionand/or an ellipsoidal portion.

FIG. 2D is planar view of an example, non-limiting embodiment of an RFfront end for a MIMO radio module 230, in this instance, a low-power,PSK and/or DPSK receiver, functioning within the communication network100 of FIG. 1 and the MIMO communication system 200 of FIG. 2A inaccordance with various aspects described herein. It is understood thatin some applications, the MIMO radio module 230 may include an OOKreceiver and/or a combination of different types of receivers that maybe interconnected to a common and/or different antennas. The exampleMIMO radio module 230 includes a substrate 231 upon which the antennacells and baseband distribution network are formed. The illustrativeradio module 230 includes four radio cells 232, four connectors 234 anda baseband distribution network 233. Each radio cell 232 is incommunication with a respective one of the connectors 234 via the RFdistribution network 233. In operation, each radio cell 232 receives awireless MIMO signal, detects bandpass information modulated onto thewireless MIMO signal at a remote MIMO transmitter, e.g., using OOK, PSKand/or DPSK modulation, and generates a detected baseband signalrepresentative of the modulated RF signal. The analog signal is passedto a signal combiner, which then passes to an ADC, e.g., a comparator,then in at least some embodiments to a digital processing unit (notshown) to determine an estimate of the transmitted informationoriginating at the MIMO transmitter. This present example embodiment maybe considered a limited implementation of the MIMO receiver 210 (FIG.2B), comprising an antenna 236, an antenna coupling/matching network 237at antenna terminal, an RF LNA, an RF signal processing/detection moduleand an envelope detector.

A first inset illustrates in more detail one of the MIMO radio cells232′. The example MIMO radio cell 232 includes a bowtie dipole antenna236, an antenna coupler 237, an RF signal processing/detection circuit238, a first stub tuner 239 and a second stub tuner 240. The RF signalprocessing/detection circuit 238 is in electrical communication with thedipole antenna via the coupler 237. A more detailed illustration of theexample antenna coupler is provided in a second inset 237′. The antennacoupler 237′ includes a capacitive arrangement adapted to block atransfer of low frequencies, e.g., DC, between the dipole antenna 236and the RF signal processing/detection circuit 238. The examplecapacitive coupler 237′ includes an inter-digitated structure extendingin length to about 100 m, with each digit of the inter-digitatedstructure having a width of about 10 m, and a separation from adjacentdigits of about 2 μm. The antenna coupler configuration 237′ ensuresthat received RF signals at the approximate operating frequencies, e.g.,K-band, are passed from the antenna 236 to the RF signalprocessing/detection circuit 238 with minimal attenuation and/ordistortion.

The RF signal processing/detection circuit 238 receives an RF signalresponsive to exposure of the dipole antenna 236 to a wireless MIMOsignal. Thus, the RF signal will depend upon the transmitted MIMO signalas adapted by a wireless RF channel between the remote transmitter andthe dipole antenna 236. To at least some extent, the RF signal willdepend on a position and/or orientation of the dipole antenna 236.Accordingly, it is expected that in at least some applications, RFsignals obtained by the different MIMO radio cells 232 when exposed tothe same wireless RF signal may differ according to channel variances.The diode is configured to rectify the received RF signal to obtain arepresentation of an amplitude or envelope of the received RF signal.The stub tuners 239 and/or 240 may facilitate impedance matching of theRF signal processing/detection circuit 238 to a transmission line and/orto other circuit elements, such as the low-resolution ADC or comparator(not shown). According to the illustrated example, the first stub tuner239 presents an open circuit at a terminal of the RF signalprocessing/detection circuit 238, at the RF frequency, which aids inimpedance matching at the RF frequency from the antenna 236 to the RFsignal processing/detection circuit 238. The second stub tuner 240presents a reactive impedance to twice the RF frequency at a terminal ofRF signal processing/detection circuit 238, which prevents leakage ofthe second harmonic into the baseband distribution network 233.

The length of the example dipole antenna 236 is about 4 mm. It is worthnoting that the dimensions of the MIMO radio cell 232′ is about 4 mm byabout 4.5 mm. Namely, the dimensions of the cell 232′ are substantiallydetermined according to a size of the antenna 236 resulting in anextremely compact form factor well adapted for positioning proximate toother such cells 232 in the example MIMO radio module 230.

The substrate 231 may include any suitable substrate that supportsconductive elements, such as radiating elements, i.e., antennas,transmission lines, and the like. Examples include, without limitation,dielectric substrates including one or more of glass, fiberglass,plastics, polymers, and/or semiconductors, e.g., silicon. Furtherexample substrates include bakelite orpolyoxybenzylmethylenglycolanhydride, commonly used as an electricalinsulator possessing considerable mechanical strength. Otheralternatives include glass-reinforced epoxy laminate sheets, tubes, rodsand printed circuit boards (PCB), such as FR-4. Still other alternativesinclude glass reinforced hydrocarbon/ceramic laminates materials, suchas RO4003® Series High Frequency Circuit Materials, PTFE laminates andglass microfiber reinforced PTFE (polytetrafluoroethylene) compositematerials, e.g., RT/Duroid® laminates, produced by Rogers Corporation.

The conductive elements, such as the antennas, matching networks,filters and/or the RF distribution networks may be configured upon thesubstrate 231. Such conductive elements may be defined by PCBfabrication processes including without limitation one or more ofchemical etching, chemical deposition, semiconductor fabricationprocesses, or combination of both PCB and semiconductor fabricationprocesses. PCB fabrication processes include, without limitation imagingdesired layout on conductor, e.g., copper, clad laminates, etching orremoving excess copper from surface and/or inner layers to define and/orotherwise reveal traces and/or device mounting pads, creating a PCBlayer stack-up by laminating, e.g., heating and pressing, boardmaterials at high temperatures, and the like. PCB fabrication processesmay include drilling holes for mounting holes, through hole pins andvias. Semiconductor fabrication processes may include one or more of adeposition that grows, coats, or otherwise transfers a material onto asubstrate, e.g., a semiconductor wafer. Available technologies include,without limitation, physical vapor deposition, chemical vapordeposition, electrochemical deposition, molecular beam epitaxy andatomic layer deposition among others.

Low-resolution, receivers with a 1-bit ADCs can be optimal in abits/Joule-sense if the RF front-end is sufficiently low-power. Theinherent nonlinearity of a 1-bit ADC permits the radio to be designed tosatisfy power constraints without regard for linearity. As disclosedherein the RF front-end may be extremely low-power (even passive).

The example energy detector is configured to operate at about 38 GHz.The energy detector may incorporate a W-band zero-bias diode (ZBD),available from Virginia Diodes, in a 50-ohm co-planar waveguide (CPW)environment with 150 μm pitch pads. The CPW metal is 20 nm Ti, 480 nm Audeposited by an electron-beam evaporation liftoff process on500-μm-thick high-resistivity (ρ>5 k Ω·cm) silicon. A single-stubnetwork matches the input to the ZBD, while two stubs at the outputprovide terminations at fc (open) and 2fc (reactive). The diode isflip-chip soldered to the pads by hotplate using low-melting-pointindium alloy solder balls. Gold wirebonds (diameter 25 μm) are used toequalize ground plane potential in the CPW, especially at stubjunctions.

FIG. 2E is a block diagram illustrating an example, non-limitingembodiment of a radio system 245 including an antenna array functioningwithin the communication network of FIG. 1 and the MIMO communicationsystem of FIG. 2A. The radio system 245 includes a digital basebandsubsystem 250 in communication with one or more of a transmittersubsystem 246 and a receiver subsystem 247. The transmitter subsystem246 includes multiple up-converter modules 254 a, 254 b . . . 254 n,generally 254. Each of the up-converter modules 254 is in communicationwith a respective transmit antenna 248 a, 248 b . . . 248 n, generally248. In at least some embodiments, the transmitter subsystem 246includes one or more transmit beam forming modules 260 a, 260 b . . .260 n, generally 260 (shown in phantom). Each of the beamforming modules260 may be communicatively coupled between respective ones of theup-converter modules 254 and the transmit antennas 248.

In operation, the transmit beamforming modules 260 may apply one or moreof a gain or a phase offset to transmit signals received from theup-converter modules 254. The gain and/or phase adjusted transmitsignals may then be routed to the antennas 248 for wireless transmissionto remote terminals. The transmit antennas 248 may function astransducers, e.g., converting currents and/or voltages of the gainand/or phase-adjusted transmit signals into electromagnetic waves. It isconceivable that the antennas 248 may include any antenna elementssuitable for operation in any intended operational frequency range orband. According to the illustrative embodiments and without limitation,the transmit antennas 248 may operate in the millimeter wave spectrum.Accordingly, such elements may include dipole antennas, monopoleantennas, loop antennas, patch antennas, aperture antennas, e.g., hornantennas and/or slot antennas, and the like.

The transmit antennas 248 generally include respective performanceparameters, such as radiation patterns, polarizations, input impedances,radiation efficiencies and the like. It is understood that groupings ofmultiple antenna elements, such as the example antennas 248, may bearranged according to a particular arrangement, generally referred to asan antenna array. It is further understood antenna arrays may includeperformance parameters, such as array patterns, e.g., beamwidth, powergain, directivity, azimuth and/or elevation angles, aperture size,nulls, steerability, and so on. It is further understood that antennaarray performance may be determined according to one or more of a typeor types of antenna element(s) used, alignment and/or orientation(s) ofthe antenna elements, e.g., linear, rectangular, conformal, spacingbetween adjacent antenna elements, e.g., uniform, non-uniform, and soon.

In at least some embodiments, such antenna array performance parametersmay be further established, adjusted and/or otherwise controlledaccording to one or more of gain or phase differences across the antennaelements of the array. In at least some embodiments, the transmit beamforming modules 260 may apply a fixed gain offset across transmitantenna elements 248 of the antenna array. Alternatively or in addition,the beam forming modules 260 may apply an adjustable gain offset. Thegain offset may include one or more of gain, e.g., amplification and/orattenuation. Likewise, in at least some embodiments, the transmit beamforming modules 260 may apply a fixed phase offset across transmitantenna elements 248 of the antenna array. Alternatively or in addition,the transmit beam forming modules 260 may apply an adjustable phaseoffset.

To the extent that one or more of the gain and/or phase of the beamforming modules 260 may be adjustable, one or more of the beam formingmodules 260 may receive a control signal (shown in phantom). The controlsignal is adapted to adjust one or more of any adjustable gain,attenuation and/or phase elements of the beam forming modules 260. Forexample, control signals may be provided by a MIMO controller, such thatthe antenna elements 248 and/or antenna array may provide mobile serviceto mobile subscriber units according to a mobile communicationsprotocol, such as the example protocols disclosed herein.

Although the example radio system 245 shows one up-converter module 254in communication with a single transmit antenna 248, it is understoodthat in at least some embodiments, one or more of the up-convertermodules 254 may be in communication with more than one transmit antennas248. For example, an antenna subarray of two or more transmit antennaelements 248 may receive a transmit signal from a single up-convertmodule 254 for transmission by the subarray of transmit antenna elements248. Alternatively or in addition, it is conceivable that more than oneup-converter elements may be in communication with a single antennaelement. Accordingly, a single transmit antenna element 248 maywirelessly transmit signals from more than one of the up-convertermodules 254. For completeness, it is further conceivable that more thanone up-converter modules 254 may be in communication with a commonsubgroup of transmit antenna elements 248, such that the subgroup oftransmit antenna elements 248 may wirelessly transmit signals from thegroup of up-converter modules. For example, a single antenna array madeup of sub-arrays may engage in simultaneous communications with morethan one wireless terminals in one or more different locations.

The example transmitter subsystem 246 receives digital baseband signalsfrom the digital baseband module 250. The digital signals may beconverted to analog signals before upconverted and wirelesslytransmitted via one or more of the antennas 248. According to theillustrative embodiment, each upconverter module 254 receives an analogsignal from a respective digital-to-analog converter (DAC) 252 a, 252 b. . . 252 n, generally 252. The digital signal may contain informationto be wirelessly transmitted by the transmit antennas 248 according to aparticular wireless communication protocol, such as the exampleprotocols disclosed herein or otherwise generally known to those skilledin the art. Accordingly, the digital signal may include signalinginformation that may be used for one or more of establishing wirelesscommunications with a remote wireless terminal, managing mobility tofacilitate delivery of wireless services to mobile terminals, and thelike. Alternatively or in addition, the digital signal may include userdata. Without limitation, user data may include voice, e.g., VoIP, audiostreaming, video streaming, text messaging, email, Web browsing,delivery of HTML pages, and the like.

The receiver subsystem 247 includes multiple down-converter modules 253a, 253 b . . . 253 n, generally 253. Each of the down-converter modules253 is in communication with a respective receive antenna 249 a, 249 b .. . 249 n, generally 249. In at least some embodiments, the receiversubsystem 247 includes one or more receive beam forming modules 259 a,259 b . . . 259 n, generally 259 (shown in phantom). Each of the receivebeamforming modules 259 may be communicatively coupled betweenrespective ones of the down-converter modules 253 and the receiveantennas 249. It is understood that configurations and/or operation ofthe receiver subsystem 247 may be similar to that described above inreference to the transmitter subsystem 246, distinguishable in that thereceive antennas 249 receive wireless signals in the form ofelectromagnetic waves and convert the received wireless signals intoreceived current and/or voltage signals suitable for processing by thedown-converter module 253, and the like.

The individual antennas 249 may include any of the aforementioned typesof transmit antennas 249. In at least some embodiments, the transmitantenna elements 248 and the receive antenna elements 249 are the sametypes of antenna elements. Alternatively or in addition, at least someof the receive antenna elements 249 may differ from the transmit antennaelements 248, e.g., according to differences in polarization, frequency,gain and/or directivity requirements, and so on. As with the transmitantennas 248, receive antenna array performance parameters may befurther established, adjusted and/or otherwise controlled according toone or more of gain or phase differences across the antenna elements ofthe array. In at least some embodiments, the receiver subsystem 247includes one or more receive beam-forming modules 259 a, 259 b . . . .259 n, generally 259. The receive beam forming modules 259 may apply afixed gain offset across receive antenna elements 249 of the antennaarray. Alternatively or in addition, the receive beam forming modules259 may apply an adjustable gain offset. The gain offset may include oneor more of gain, e.g., amplification and/or attenuation. Likewise, in atleast some embodiments, the receive beam forming modules 259 may apply afixed phase offset across receive antenna elements 249 of the antennaarray. Alternatively or in addition, the receive beam forming modules259 may apply an adjustable phase offset.

The example receiver subsystem 247 provides digital baseband signals tothe digital baseband module 250. Received analog signals obtained fromreceived wireless signals may be converted to digital signals beforedown converted. According to the illustrative embodiment, eachdownconverter module 254 receives an analog signal from a respectivereceive antenna element 249 and provides a corresponding down-convertedand/or detected signal to a respective one of a number ofanalog-to-digital converters (ADC) 251 a, 251 b . . . 251 n, generally251. The received analog signal may contain information received by thereceive antennas 249 according to a particular wireless communicationprotocol, such as the example protocols disclosed herein or otherwisegenerally known to those skilled in the art. Accordingly, the received,converted digital signal may include signaling information that may beused for one or more of establishing wireless communications with aremote wireless terminal, managing mobility to facilitate delivery ofwireless services to mobile terminals, and the like. Alternatively or inaddition, the digital signal may include user data. Without limitation,user data may include voice, e.g., VoIP, audio streaming, videostreaming, text messaging, email, Web browsing, delivery of HTML pages,and the like.

It is understood that operation of complex communication systems, suchas the example radio system 245, may require precise timing across largenumbers of components. For example, antenna arrays including multipleantenna elements 248, 249 may require precise control of one or more offrequency, phase, or time across the transmit antenna elements 248and/or the receive antenna elements 249. Such precision may be necessaryto ensure proper operation of the radio system 245, e.g., according toany applicable communication protocol. For example, phase coherence maybe necessary to ensure proper operation of an antenna array, e.g.,supporting the array's gain, and/or directivity, and/or beamwidth,and/or null-steering and the like. Alternatively or in addition,ensuring frequency and/or phase synchronization, e.g., coherence,according to a predetermined threshold may be necessary to ensure one ormore of modulation, demodulation, data synchronization, and so on. Tothis end, the example radio system includes certain components and/orsubsystems adapted to facilitate control of one or more of frequency,phase, or time across the transmit antenna elements 248 and/or thereceive antenna elements 249, at least to within a predetermined value,e.g., a threshold value.

According to the illustrative example, each of the upconverter modules254 may include a respective synchronization module 256 a, 256 b . . .256 n, generally 256, e.g., including an adjustable LO. According to theexample techniques disclosed herein, one or more of a phase and/or afrequency of the adjustable LO may be maintained to within apredetermined accuracy with the adjustable LOs of one or more othersynchronization modules 256. Likewise, each of the down-converter module253 may include a respective synchronization module 255 a, 255 b . . .255 n, generally 255, e.g., including an adjustable LO. According to theexample techniques disclosed herein, one or more of a phase and/or afrequency of the adjustable LO may be maintained to within apredetermined accuracy with the adjustable LOs of one or more othersynchronization modules 255. In at least some embodiments, one or moreof the synchronization modules 256 of the transmitter subsystem 246 maybe synchronized, e.g., coherent, with one or more of the synchronizationmodules 255 of the receiver module 247.

It can be appreciated that establishing and/or maintaining suchsynchronization, which may include phase coherence, is a difficultchallenge, particularly at higher frequencies, such as the examplemillimeter wave band and for large numbers of up and down-convertermodules 254, 253 and large numbers of antenna elements 248, 249. Inparticular, massive MIMO arrays may include hundreds, or perhaps eventhousands or tens of thousands of such up and down down-convertermodules 254, 253 and/or antenna elements 248, 249. One such solutionwould be to provide a common LO, which would be distributed to each ofthe up and down-converter modules 254, 253. To the extent that an RFsignal of the common LO is divided among the different synchronizationmodules 255, 256, a substantial power would be required. Consider anexample power requirement of about 0 dBm LO level at each thesynchronization modules 255, 256. A modest massive MIMO system with1,000 elements would then require a master LO power level of at least 30dBm, before power division. Considering signal loss and inefficienciesof any realizable system, a stable millimeter wave source providing morethan 1 Watt at operational frequencies would be required. Suchchallenges would be complex and costly, at the very least, if notaltogether impossible for at least some configurations.

Another approach would be to include multiple LOs phase locked to amaster LO. Some combination of power division and duplication could beapplied. Consider 10 LOs, each supporting 100 synchronization modules255, 256 of the example 1,000 element massive MIMO system. Suchduplication of LOs would reduce power requirements, e.g., with each LOoperating at 20 dBm. However, there remains a challenge of establishingand maintaining synchronization, e.g., phase coherence, of the exampleten LOs. Even if it were possible to maintain phase coherence of the tenLOs, a 0.1 mW requirement may be costly and complex at millimeter wavefrequencies.

The illustrative embodiment provides an adjustable LO at each of thesynchronization modules 255, 256. The radio system 245 also includes acommon timing reference 257 and a timing distribution network 258. Thetiming distribution network 258 is communicatively coupled between thetiming reference 257 and one or more of the synchronization modules 255,256. According to the illustrative example, the timing reference 257 maya pulse generator adapted to generate one or more timing pulses. In atleast some embodiments, the timing reference 257 includes a master LO,from which the timing pulses may be synchronized.

In some embodiments, a timing pulse may be provided at a pulse widthand/or pulse repetition frequency that is substantially lower than anoperational frequency of the master LO. For example, the timing pulsemay be one or more orders of magnitude lower than an operationalfrequency of the master LO. Consider an example system in which themaster LO operates at 1 GHz. The timing pulse may be generated accordingto about 10 MHz, i.e., 100 times lower frequency. In at least someembodiments, the timing distribution network receives one or more timingpulses from the timing reference 257 and distributes the timing pulsesto one or more of the synchronization modules 255, 256. According to theillustrative embodiment, the timing distribution network 258 is incommunication with each of the synchronization modules 255, 256,providing a timing reference to one or more of the synchronizationmodules 255, 256 as necessary.

In some embodiments, some, conceivably all of the synchronizationmodules 255, 256 receive a timing pulse from the timing reference by wayof the timing distribution network 258. For example, eachsynchronization modules 255, 256 may receive the same timing pulse, suchthat the synchronization modules 255, 256 may adjust their respectiveadjustable LOs to achieve synchronization, e.g., coherence.Alternatively or in addition, at least some of the synchronizationmodules 255, 256 may receive one timing pulse while at least one otherof the synchronization modules 255, 256 receives a different timingpulse, both pulses of this example originating from the timing reference257 and distributed accordingly by the timing distribution network 258.In at least some embodiments, many and perhaps all of thesynchronization modules 255, 256 receive a respective pulse from thetiming reference via the timing distribution network 258. In anyinstance, the synchronization modules 255, 256 use their respectivetiming pulses to achieve synchronization, e.g., coherence, with othersynchronization modules 255, 256 of the radio system 245.

It is worth noting that although the transmitter subsystem 246 isillustrated as being coupled to a first group of antennas 248 and thereceiver subsystem 247 is illustrated as being coupled to a second groupof antennas 248, it is understood that in at least some embodiments, thereceiver and transmitter subsystems 246, 247 may share a common group ofantennas. For example, a single antenna array, e.g., the first group ofantennas 248 may be used for both transmission and reception of wirelesssignals according to the applicable protocol. Alternatively or inaddition, although separate transmitter and receiver subsystems 246, 247are illustrated, it is understood that in at least some embodiments, acommon transceiver module may perform both of the transmit and receiveoperations. Accordingly, a single adjustable LO may suffice for bothup-converter and down-converter operation within a single transceivermodule, thereby substantially reducing the number of required adjustableLOs, e.g., by a factor of two.

FIG. 2F is a block diagram illustrating an example, non-limitingembodiment of a distributed, synchronized, e.g., coherent, LO system 265functioning with the communication network of FIG. 1, the MIMOcommunication system of FIG. 2A, and the radio system of FIG. 2E inaccordance with various aspects described herein. The synchronized LOsystem 265 includes a common timing reference 266, a timing pulsegenerator 267 and a timing distribution network 268. The synchronized LOsystem 265 further includes multiple adjustable LOs 269 a, 269 b . . .269 n, generally 269.

According to the illustrative example, a master LO of the common timingreference 266 feeds into a pulse generation system of the timing pulsegenerator 267, which generates regular pulses based on an operationalfrequency of the master LO of the common timing reference 266. Theregular pulses, in turn, are fed from the timing pulse generator 267 tothe timing distribution network 268, which distributes the regularpulses to one or more of the adjustable LOs 269. The timing pulses mayinclude RF signals that may be distributed between one or more of thetiming distribution network 268 and the adjustable LOs 269 usingsuitable transmission lines. Alternatively or in addition, the timingpulses may include digital signals that ma be distributed usingtransmission lines and/or wiring or cabling and/or printed circuit boardtraces, flex lines, and the like. Transmission lines may include,without limitation, any of the example transmission lines disclosedherein or otherwise known to those skilled in the art, including withoutlimitation, coaxial cable, unshielded twisted pair, shielded twistedpair, strip line, microstrip, waveguide, fiberoptic cables, and thelike.

The timing distribution network 268 may include one or more of a powerdivider and/or power combiner, such as a Wilkinson powerdivider/combiner. Alternatively or in addition, the timing distributionnetwork may include nodes, such as interconnections of wires and/or PCBtraces. Still other signal splitters and/or combiners may include RFcouplers, such as hybrid couplers adapted to combine and/or split powerbetween coupler ports according to a prescribed phase offset, e.g., ±90°and/or ±180° and so on.

Alternatively or in addition, the riming distribution network 268 mayinclude one or more switches. The switches may operable according to aswitch control signal to direct timing pulses according to apredetermined routing schedule. By way of nonlimiting example, theswitches may include single pole, single throw (SPST) type switches thatconnect and/or disconnect the pulse generator 267 to one or moreselective ones of the correctable LOs 269. Other types of switches mayinclude single pole, double throw (SPDT) type switches that selectivelyconnect the pulse generator 267 to one of two switched correctable LOs269. In at least some embodiments, the timing distribution network 268includes a switch matrix configured to switch a single timing pulseand/or single timing pulse train of a group of timing pulses to one ormore of the correctable LOs 269. The switches and/or switch matrix mayinclude mechanical switches, e.g., servo controlled. Alternatively or inaddition, the switches and/or switch matrix may include semiconductorswitches, e.g., transistor switches.

The switches may actuate, i.e., switch, according to a switching controlsignal. The switching control signal may be received from a separatecontroller, not shown, such as a MIMO antenna controller. Alternativelyor in addition, the switching control signal may be received from aradio module timing distribution controller. For example, the radiomodule timing distribution controller provides a switching controlsignal that selectively connects one or more of the correctable LOs 269to the timing pulse generator 267. The switching control signal may beadapted to switch control in a systematic and repeatable manner, e.g.,each correctable LO 269 of a group of correctable LOs 269 receiving atiming pulse within a timing pulse window, while other correctable LOs269 do not receive any timing pulse during the same timing pulse window.Different correctable LOs 269 may receive respective timing pulsesduring respectively different timing pulse windows. Different timingpulse windows may be allocated to different correctable LOs 269 orgroups of correctable LOs 269, with a refresh rate, such thatsynchronization may be maintained.

It is conceivable that in at least some embodiments, one or more of thetiming pulse window size and/or number of timing pulse windows between arepeated of the timing pulse windows may depend upon one or more of afrequency of operation, a type of modulation applied to RF signalsprocessed according to the corrected LOs 269, applicable wirelessprotocol, observable error rates, temperature, RF propagationcharacteristics, e.g., quality of service (QoS), channel parameters,class of service, type of service, and the like.

In at least some embodiments, the LO system 265 includes one or morefrequency multipliers 270 a, 270 b . . . 270 n, generally 270. Forexample, a corrected LO 269 provides a sable, synchronized, e.g.,coherent, output at a first frequency, say 8 GHz, yet the requiredfrequency of operation is about 32 GHz. In such instances, an output ofthe corrected LO 269 is provided to the multiplier 270, which mayinclude a nonlinear element adapted to provide an output signalobtaining harmonics of the applied input signal. According to theillustrative example, a fourth harmonic of the 8 GHz signal wouldprovide a stable, synchronized signal at the operating frequency of 32GHz. It is understood that a frequency multiplier 270 may includefilters and/or other signal conditioning elements adapted to attenuateand/or otherwise remove unwanted signal components, e.g., at frequenciesoutside of an intended operational frequency range, while passing thosesignals within the intended operational frequency range.

FIG. 2G depicts a graphical representation of LO synchronization signals285 according LO correction system functioning with the communicationnetwork of FIG. 1, the MIMO communication system of FIG. 2A, the radiosystem of FIG. 2E, and the distributed, coherent LO system of FIG. 2F inaccordance with various aspects described herein. A portion of acorrected LO output 286 of an adjustable LO, e.g., of the correctable LO269 (FIG. 2F) and/or the adjustable LO of the synchronization modules255, 256 (FIG. 2E). The example corrected LO output 286 is a sinusoidhaving a frequency f_(LO) and a period of 1/f_(LO). It is understoodthat the adjustable LO producing the corrected LO output 286 may becontrolled to vary the corrected LO frequency. Namely if an LO frequencyf_(LO)′ is not synchronized to some reference, e.g., the timing pulseand/or the master oscillator, then a control signal is applied to theadjustable LO to vary the operational frequency in a manner adapted tocorrect the error. That is, if the LO frequency is too high, i.e.,f_(LO)′>f_(LO_Target), then the adjustable LO is adjusted to reduce thefrequency. The control signal may be obtained from an error signaldetermined according to a difference between the adjusted LO output andthe target and/or synchronized frequency. The control signal may beapplied to the adjustable LO in a feedback loop, e.g., as in a phaselock loop (PLL).

The graphical representation of LO synchronization signals 285 includesfurther detail regarding generation of the timing pulses. By way ofillustrative example, the pulse generator 267 (FIG. 2F) provides a pulsesignal 287. In at least some embodiments, the pulse signal 287 is aperiodic signal repeating with a clock period t_(clk). The pulse signal287 may obtained as a substantially square wave, e.g., a digital signal.Alternatively or in addition, the pulse signal may take on other waveshapes, such as sinusoids, offset sinusoids, and the like. The pulsesignal may have a duty cycle that describes a variation between a “high”value of the pulse and a “low” value of the pulse. According to theillustrative example, and without limitation, the high value has a pulsewidth of p, and a duty cycle of about 50%. Successive pulse cycles occurat respective times, e.g., a first reference pulse at t₁, a second pulseat t₂ and an nth pulse at t_(n). In at least some embodiments, theindividual pulse times may be relative to an arbitrary time period,e.g., according to a pulse identified as a reference pulse.

In some embodiments one or more switched pulses 288 a, 288 b . . . 288n, generally 288, are obtained. A first switched pulse 288 a provides a“high” pulse portion beginning at a reference pulse time t₁ and lastingfor a pulse period of p. The first switched pulse 288 a may be providedto a first selective one of the adjustable LO, e.g., of the correctableLO 269 (FIG. 2F) and/or a first selective one of the adjustable LO ofthe synchronization modules 255, 256 (FIG. 2E). The switched pulsesignal may remain in a “low” state until another pulse having a “high”state is received at a later time. According to the illustrativeexample, a time period between successive “high” portions or pulses ofthe first switched pulse 288 a, is a pulse repetition time T. In thismanner, a single pulse having pulse width p is provided by the firstswitched pulse 288 a every T seconds. In at least some embodiments, thepulse, e.g., a rising and/or falling edge of the pulse, and/or the timebetween successive pulses, may be used to detect a difference betweenthe operational frequency of the adjustable LO and a referencesynchronization source, such as the master oscillator, to ensuresynchronization within the radio system 245.

Continuing with the illustrative example, a second switched pulse 288 bprovides a “high” pulse portion beginning at a reference pulse time t₂and lasting for a pulse period of p. The second switched pulse 288 b maybe provided to a second selective one of the adjustable LO, e.g., of thecorrectable LO 269 (FIG. 2F) and/or a second selective one of theadjustable LO of the synchronization modules 255, 256 (FIG. 2E). In thisexample, the second switched pulse occurs at a time t₂, and remains“high” for a period p, repeating according to a pulse repetition rate,e.g., the same time period T as in the aforementioned first switchedpulse 288 c. Additional switched pulses 288 may continue in a likemanner, each one being offset from at least some of the others by one ormore clock periods t_(clk). Here, N pulses are provided before any ofthe pulses repeat.

It is important to appreciate that the pulses do not overlap. Thus,power handling concerns of power splitting a pulse may be avoided, byproviding full power pulses to one or more individual and/or subgroupsof the adjustable LOs. For example, a pulse repetition rate T may beselected, determined or otherwise calculated as a maximum period bywhich the adjustable LO frequency may drift before requiring anadjustment to maintain a desired level of synchronization, e.g.,coherence. Similarly, the pulse widths p, may be determined according toa number N of switched timing pulses required to serve the adjustableLOs.

Consider an example in which 1000 adjustable LOs are service by a singletiming pulse generator 267, and that pulse repetition rate can be nomore than about 1 sec for ant one adjustable LO. Accordingly, the pulserepetition rate T-1 sec, and the pulse width p=0.5 msec as the pulserepetition period is divided 1000 times, with one pulse for eachadjustable LO, and assuming a 50% duty cycle. If greater numbers ofadjustable LOs are used that might otherwise be serviced by a singletiming pulse generator and switching configuration, it is understoodthat a combination of pulse signal division and/or switching may beapplied.

Consider another example in which 1000 presents a maximum practicallimit of adjustable LOs that may be serviced by the switching network.In this example, the reference timing pulse trains may be divided intotwo coherent reference timing pulse trains. Each pulse train may bedistributed according to a respective switching network adapted toprovide pulses to 1000 elements, such that the combined approach permitsthe 2000 elements to be operated in a synchronized, e.g., coherent,manner.

FIG. 2H is a block diagram illustrating an example, non-limitingembodiment of a corrected LO 275 functioning with the communicationnetwork of FIG. 1, the MIMO communication system of FIG. 2A, the radiosystem of FIG. 2E, and the distributed, coherent LO system of FIG. 2F inaccordance with various aspects described herein. The example correctedLO system 275 includes a counter 276, an error detector 278, a loopfilter 279 and an adjustable LO 277.

In more detail, the corrected LO 275 includes a first port 280′ or inputterminal in communication with a remote timing source, such as thetiming pulse generator 267 via the timing distribution network 268 (FIG.2F) and/or the timing reference 257 via the switching network 258 (FIG.2E). The counter 276 is in communication with the first port 280′,receiving therefrom a timing reference signal. The counter 276 is alsoin communication with the adjustable LO 277. For example the counter mayreceive a sample of the adjusted LO output at the LO frequency. Thecounter 276 may be adapted to count cycles of the adjusted LO outputoccurring between consecutive timing pulses, e.g., between consecutivepulses of the first switched pulse 288 a (FIG. 2G). Accordingly,initiation of pulse counting may occur upon receipt of the firstswitched pulse 288 a. Counting of the adjusted LO output cycles maycontinue until a subsequent pulse is provided according to the firstswitched pulse 288 a, e.g., after a time period T. Upon detection of thesubsequent pulse, the count value may be provided and/or otherwiseforwarded to the error detector 278. In at least some embodiments, thecounter is reinitialized, e.g., reset, and begins a second subsequentcounting output cycles of the adjusted LO 277.

The error detector 278 compares the count value to a reference countvalue. The error detector 278 may provide an output, e.g., an errorsignal, indicative of a difference between the count value obtained fromthe counter 276 and the reference value. In some embodiments, the errorsignal may include a sign indicating whether the difference is greateror lesser than the reference value. Alternatively or in addition, theerror signal may include a magnitude indicative of a magnitude of thedifference. The error signal may be provided to a control terminal ofthe adjustable LO 277 to induce a change in an operating frequency ofthe adjustable LO 277, such that the change tends to direct the adjustedLO output of the adjustable LO 277 to a synchronized value. It isunderstood that in at least some embodiments, a loop filter may beprovided between the error detector 278 and the control terminal of theadjustable LO 277. According to the illustrative example, the loopfilter includes an integrator. The integrator integrates the errorsignal in order to provide a control signal to the control terminal ofthe adjustable LO 277 that is adapted to establish and/or otherwisemaintain the adjusted LO output according to a synchronized value. It isunderstood that similar corrected LOs 275 receiving respective differentpulses from the timing distribution network may operate in a like mannerto obtain adjusted LO outputs corresponding to a common synchronizedvalue. The adjusted LO output may be provided to an output port orterminal 280″.

In summary and according to the illustrative example, the counter 276accumulates a number of LO cycles occurring within a trigger period, T.A digital output of the counter, e.g., a number may be compared to areference number to determine a difference between the two numbers. Atleast some general-purpose frequency counters may include some form ofamplifier, filtering and shaping circuitry at the input. It isunderstood that at least some designs may use a high-speed pre-scaler tobring the signal frequency down to a point where normal digitalcircuitry can operate. An error signal is determined from the output andmay be integrated and used to drive a voltage-controlled oscillator(VCO), by adjusting its output in order to minimize count error. Moregenerally, it is understood that DSP technology, sensitivity control andhysteresis are other techniques that may be incorporated to improveperformance. The adjusted LO output may be used to modulate and/ordemodulate and/or upconvert and/or down convert signals as may berequired according to operation of radio communication systems, such asthe example massive MIMO systems operating in the millimeter wavespectrum.

FIG. 2I depicts an illustrative embodiment of a process 290 thatestablishes synchronization of large numbers of LOs operating within amillimeter wave system in accordance with various aspects describedherein. A timing reference signal is generated at 291. The timing signalreference may include a single timing reference, e.g., a pulse train,that is obtained in a synchronous manner with respect to a masteroscillator. The timing signal may be an RF signal and/or a digitalsignal. The timing signal may include pulses provided at a pulserepetition frequency that is substantially less than an LO frequency ofany up and/or down converters and/or any operational RF frequency ofwireless signals processed by the example radios.

Multiple timing signal segments may be obtained at 292 based upon thereference timing signal. In some embodiments, the multiple timingsignals are obtained by a power division of the timing reference signal.For example, the timing reference signal may be divided by a powerdivision circuit, such as the example device disclosed herein, to obtainmultiple, synchronized timing reference signals. Alternatively or inaddition, the multiple timing signals may be obtained from a time-basedslicing of the single pulse signal. Different pulses of the single pulsetrain may be demultiplexed and/or otherwise separated from the pulsetrain, such that multiple independent, non-overlapping timing pulsesignals are obtained. Such a demultiplexing process may be accomplishedby an array of switches operated to sequentially switch sequentialpulses of the timing pulse train to different switched outputs. Thedifferent switched timing signal segments may be provided to differentradio modules at 293, e.g., by routing the outputs of different switchesto different radio modules.

At each of the radio modules, cycles of a respective LO may be countedat 294 to obtain a respective count value for each radio module. Forexample, each radio module may include a counter that is clocked by anadjusted LO output signal. The counter may have a reset that resets thecount to an initial value, e.g., “0.” In at least some embodiments, thereset may be connected to a respective switched timing signal, such thatthe counter obtains a count equivalent to a number of adjusted LO cyclesbetween consecutive pulses of the switched timing signal.

At each of the radio modules, differences between the respective countvalues and a reference value are determined at 295. For example, thecount value obtained at 294 may be compared to a reference value, suchas a target, synchronized LO frequency. A difference between the countvalue and the reference value provides a measure of a departure from theadjusted LO to the target, synchronized LO frequency. The differencevalue may be used to generate an error signal that may be used to adjustthe adjustable LO in a corrective manner, bring its operating frequencyinto conformity with the target, synchronized LO frequency. Namely, ateach of the radio modules, a respective LO is adjusted at 296 accordingto a respective count difference to obtain an adjusted LO signal.Consequently, the adjusted count signals of the multiple radio modulestrend towards synchronization with respect to each other. The processmay be implemented across all radio modules and repeated in a periodic,aperiodic and/or substantially continuous manner.

In at least some embodiments, a spatially diverse wireless signal may bereceived that may include a spatially multiplexed signal and/orspatially diverse signals resulting from multipath propagation between atransmitter portion 201 and a receiver portion 202 (FIG. 2A). In atleast some embodiments, the spatially diverse wireless signal may beobtained according to a MIMO process, such as those described inassociation with new radio and/or Next Generation Long Term EvolutionLTE) wireless radio communications. In at least some embodiments, thereceiving is accomplished using a transducer, such as an antenna element211 (FIG. 2B) adapted to generate a received RF signal at an antennaterminal 212 (FIG. 2B) of the antenna 211 responsive to the spatiallydiverse wireless signal impingent upon the antenna element 211.

A received RF signal may be combined with a synchronized LO signalobtained according to the techniques disclosed herein. In at least someembodiments, the synchronized LO signal is a low-power LO signal. Acombining of synchronized LO with the received signals may beaccomplished by summing the signals in a power sense.

The combined signal may be coupled to an energy detector of the RFprocessing/detection module 215 (FIG. 2B), such as a diode. The couplingmay be accomplished by an electrical conductor, e.g., a transmissionline extending between the antenna terminal 212 and the energy detector.Alternatively or in addition, the coupling may include one or more of anantenna coupler 213 (FIG. 2B), a balun, a filter, and the like.

In at least some embodiments, signal conditioning may be applied in anyone or more of the signal paths disclosed herein. Signal paths mayinclude transmit and/or received RF signal paths, LO signal paths,timing distribution signal paths, switched timing signal paths, and thelike. Signal conditioning may include an application of amplitude and/orgain. For example, a received RF signal is amplified, e.g., by an LNA214 (FIG. 2B) before being applied to a detector of the RFprocessing/detection module 215. Other signal conditioning may includeattenuating interference. Still other signal conditioning may includematching networks, baluns and the like.

The techniques disclosed herein may be used in combination withlow-resolution transmitters and/or receivers. For example, a basebandsignal may be detected from a received RF signal combined, e.g., summed,with an adjusted LO signal. For example, a detector may be adapted todetect baseband information from the received RF signal, the basebandbeing obtained by a mixing performed at the detector and/or diode. Inparticular, the mixing is facilitated by the low-power operation of theLO. Namely, a maximum power of the LO alone, or in combination with thereceived RF signal is sufficiently low to preserve operation of thedetector, e.g., diode, in a nonlinear region of its characteristiccurve. This may be accomplished, in the case of a diode detector bypreventing the junction from turning on.

For example, the detecting may detect an amplitude and/or an envelope ofthe received RF signal. In at least some embodiments, detection includesapplying the received RF signal to a power detector and applying alow-pass filter to the resulting signal. Alternatively or in additiondetection includes applying the received RF signal to a square-lawdetector. In at least some embodiments, the detecting includes applyingthe received RF signal to an electrical device having a nonlinear I-Vcharacteristic curve. In at least some embodiments the electrical devicemay be an active device, such as a transistor. Alternatively or inaddition, the electrical device may be a passive device, such as adiode.

In at least some embodiments, the detected signal may be digitized. Adigitizing process may be accomplished using a low resolution, e.g., asingle-bit ADC 217 (FIG. 2B). The ADC 217 may include a nonlinearprocess, such as a comparison of the detected signal to a reference,e.g., a threshold voltage. A value of a digital output of the ADC 217 isdetermined according to a result of the comparison to obtain a binary 1or a binary 0, as the case may be.

In at least some embodiments, estimates are obtained of informationtransmitted over a wireless channel 208 (FIG. 2A) via a spatiallydiverse wireless signal. In at least some embodiments, the estimation isobtained via digital signal processing of digital signals obtained fromone or more MIMO radio cells 210 (FIG. 2B) or modules 220 (FIG. 2C).Digital signal processing may include, without limitation, a combiningof digital signals obtained from at least some of the cells 222, and/ormodules 230.

It is envisioned that beamforming may be applied at a spatial diversitytransmitter, e.g., a MIMO transmitter. In particular, a massively MIMOsignal may employ beamforming to direct MIMO signals to one or moreparticular spatially diverse receivers. In at least some embodiments,beamforming may be applied at the receiver, e.g., steering an antennabeam towards one or more directions of the spatially diverse signals.However, according to the various examples disclosed herein it isenvisioned that the example MIMO receiver portions 202 (FIG. 2A), MIMOcells 222 and/or modules 220 (FIG. 2B) may operate without applyingbeamforming. Such a relaxation with respect to beamforming relaxesspacing and/or separation, and/or orientation of multiple antennas 211(FIG. 2B). Likewise, such as relaxation of beamforming at the MIMOreceiver portion 202 is consistent with the overall low-power,low-complexity architecture. Accordingly, phase control elements, suchas phase shifters, delay lines, and the like are unnecessary at thereceiver portion 202.

While for purposes of simplicity of explanation, the respectiveprocesses are shown and described as a series of blocks in FIG. 2I, itis to be understood and appreciated that the claimed subject matter isnot limited by the order of the blocks, as some blocks may occur indifferent orders and/or concurrently with other blocks from what isdepicted and described herein. Moreover, not all illustrated blocks maybe required to implement the methods described herein.

Referring now to FIG. 3, a block diagram is shown illustrating anexample, non-limiting embodiment of a virtualized communication network300 in accordance with various aspects described herein. In particular avirtualized communication network is presented that can be used toimplement some or all of the subsystems and functions of communicationnetwork 100, the subsystems and functions of the example systems 200,modules or devices 210, 220, 230, 245, 265, 278 and example process 290presented in FIGS. 1, 2A, 2B, 2C, 2D, 2E, 2F, 2H, 2I and 3. For example,virtualized communication network 300 can include functionality 382,e.g., in one or more VNEs 332 adapted to facilitate in whole or in partreceiving, by a first radio module at a first location, a wireless MIMOsignal, to obtain a first received RF signal. The wireless MIMO signalincludes information originating at a remote MIMO transmitter andconveyed via a wireless channel. An envelope of the first received RFsignal is detected by the first radio module without requiring a localoscillator, to obtain a first detected baseband signal. The firstdetected baseband signal is compared to a reference value to obtain afirst digital signal that is provided to a digital processor. Thedigital processor also obtains a second digital signal from a secondradio module receiving the wireless MIMO signal at a second location anddetermines an estimate of the information originating at the remote MIMOtransmitter according to the first and second digital signals.

In particular, a cloud networking architecture is shown that leveragescloud technologies and supports rapid innovation and scalability via atransport layer 350, a virtualized network function cloud 325 and/or oneor more cloud computing environments 375. In various embodiments, thiscloud networking architecture is an open architecture that leveragesapplication programming interfaces (APIs); reduces complexity fromservices and operations; supports more nimble business models; andrapidly and seamlessly scales to meet evolving customer requirementsincluding traffic growth, diversity of traffic types, and diversity ofperformance and reliability expectations.

In contrast to traditional network elements—which are typicallyintegrated to perform a single function, the virtualized communicationnetwork employs virtual network elements (VNEs) 330, 332, 334, etc.,that perform some or all of the functions of network elements 150, 152,154, 156, etc., For example, the network architecture can provide asubstrate of networking capability, often called Network FunctionVirtualization Infrastructure (NFVI) or simply infrastructure that iscapable of being directed with software and Software Defined Networking(SDN) protocols to perform a broad variety of network functions andservices. This infrastructure can include several types of substrates.The most typical type of substrate being servers that support NetworkFunction Virtualization (NFV), followed by packet forwardingcapabilities based on generic computing resources, with specializednetwork technologies brought to bear when general purpose processors orgeneral purpose integrated circuit devices offered by merchants(referred to herein as merchant silicon) are not appropriate. In thiscase, communication services can be implemented as cloud-centricworkloads.

As an example, a traditional network element 150 (shown in FIG. 1), suchas an edge router can be implemented via a VNE 330 composed of NFVsoftware modules, merchant silicon, and associated controllers. Thesoftware can be written so that increasing workload consumes incrementalresources from a common resource pool, and moreover so that it iselastic: so the resources are only consumed when needed. In a similarfashion, other network elements such as other routers, switches, edgecaches, and middle-boxes are instantiated from the common resource pool.Such sharing of infrastructure across a broad set of uses makes planningand growing infrastructure easier to manage.

In an embodiment, the transport layer 350 includes fiber, cable, wiredand/or wireless transport elements, network elements and interfaces toprovide broadband access 110, wireless access 120, voice access 130,media access 140 and/or access to content sources 175 for distributionof content to any or all of the access technologies. In particular, insome cases a network element needs to be positioned at a specific place,and this allows for less sharing of common infrastructure. Other times,the network elements have specific physical layer adapters that cannotbe abstracted or virtualized and might require special DSP code andanalog front-ends (AFEs) that do not lend themselves to implementationas VNEs 330, 332 or 334. These network elements can be included intransport layer 350. It is understood that in at least some embodiments,the wireless access 120 may be adapted to include a low-power MIMO radio383 having an OOK and/or PSK transmitter, and/or an OOK and/or PSKreceiver and/or an OOK and/or PSK transceiver according to thelow-power, low-complexity radios and related devices disclosed herein.

The virtualized network function cloud 325 interfaces with the transportlayer 350 to provide the VNEs 330, 332, 334, etc., to provide specificNFVs. In particular, the virtualized network function cloud 325leverages cloud operations, applications, and architectures to supportnetworking workloads. The virtualized network elements 330, 332 and 334can employ network function software that provides either a one-for-onemapping of traditional network element function or alternately somecombination of network functions designed for cloud computing. Forexample, VNEs 330, 332 and 334 can include route reflectors, domain namesystem (DNS) servers, and dynamic host configuration protocol (DHCP)servers, system architecture evolution (SAE) and/or mobility managemententity (MME) gateways, broadband network gateways, IP edge routers forIP-VPN, Ethernet and other services, load balancers, distributers andother network elements. Because these elements don't typically need toforward large amounts of traffic, their workload can be distributedacross a number of servers—each of which adds a portion of thecapability, and overall which creates an elastic function with higheravailability than its former monolithic version. These virtual networkelements 330, 332, 334, etc., can be instantiated and managed using anorchestration approach similar to those used in cloud compute services.

The cloud computing environments 375 can interface with the virtualizednetwork function cloud 325 via APIs that expose functional capabilitiesof the VNEs 330, 332, 334, etc., to provide the flexible and expandedcapabilities to the virtualized network function cloud 325. Inparticular, network workloads may have applications distributed acrossthe virtualized network function cloud 325 and cloud computingenvironment 375 and in the commercial cloud or might simply orchestrateworkloads supported entirely in NFV infrastructure from thesethird-party locations.

Turning now to FIG. 4, there is illustrated a block diagram of acomputing environment in accordance with various aspects describedherein. In order to provide additional context for various embodimentsof the embodiments described herein, FIG. 4 and the following discussionare intended to provide a brief, general description of a suitablecomputing environment 400 in which the various embodiments of thesubject disclosure can be implemented. In particular, computingenvironment 400 can be used in the implementation of network elements150, 152, 154, 156, access terminal 112, base station or access point122, switching device 132, media terminal 142, and/or VNEs 330, 332,334, etc. Each of these devices can be implemented viacomputer-executable instructions that can run on one or more computers,and/or in combination with other program modules and/or as a combinationof hardware and software. For example, computing environment 400 canfacilitate in whole or in part receiving, by a first radio module at afirst location, a wireless MIMO signal, to obtain a first received RFsignal. The wireless MIMO signal includes information originating at aremote MIMO transmitter and conveyed via a wireless channel. An envelopeof the first received RF signal is detected by the first radio modulewithout requiring a local oscillator, to obtain a first detectedbaseband signal. The first detected baseband signal is compared to areference value to obtain a first digital signal that is provided to adigital processor. The digital processor also obtains a second digitalsignal from a second radio module receiving the wireless MIMO signal ata second location and determines an estimate of the informationoriginating at the remote MIMO transmitter according to the first andsecond digital signals.

Generally, program modules comprise routines, programs, components, datastructures, etc., that perform particular tasks or implement particularabstract data types. Moreover, those skilled in the art will appreciatethat the methods can be practiced with other computer systemconfigurations, comprising single-processor or multiprocessor computersystems, minicomputers, mainframe computers, as well as personalcomputers, hand-held computing devices, microprocessor-based orprogrammable consumer electronics, and the like, each of which can beoperatively coupled to one or more associated devices.

As used herein, a processing circuit includes one or more processors aswell as other application specific circuits such as an applicationspecific integrated circuit, digital logic circuit, state machine,programmable gate array or other circuit that processes input signals ordata and that produces output signals or data in response thereto. Itshould be noted that while any functions and features described hereinin association with the operation of a processor could likewise beperformed by a processing circuit.

The illustrated embodiments of the embodiments herein can be alsopracticed in distributed computing environments where certain tasks areperformed by remote processing devices that are linked through acommunications network. In a distributed computing environment, programmodules can be located in both local and remote memory storage devices.

Computing devices typically comprise a variety of media, which cancomprise computer-readable storage media and/or communications media,which two terms are used herein differently from one another as follows.Computer-readable storage media can be any available storage media thatcan be accessed by the computer and comprises both volatile andnonvolatile media, removable and non-removable media. By way of example,and not limitation, computer-readable storage media can be implementedin connection with any method or technology for storage of informationsuch as computer-readable instructions, program modules, structured dataor unstructured data.

Computer-readable storage media can comprise, but are not limited to,random access memory (RAM), read only memory (ROM), electricallyerasable programmable read only memory (EEPROM), flash memory or othermemory technology, compact disk read only memory (CD-ROM), digitalversatile disk (DVD) or other optical disk storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devicesor other tangible and/or non-transitory media which can be used to storedesired information. In this regard, the terms “tangible” or“non-transitory” herein as applied to storage, memory orcomputer-readable media, are to be understood to exclude onlypropagating transitory signals per se as modifiers and do not relinquishrights to all standard storage, memory or computer-readable media thatare not only propagating transitory signals per se.

Computer-readable storage media can be accessed by one or more local orremote computing devices, e.g., via access requests, queries, or otherdata retrieval protocols, for a variety of operations with respect tothe information stored by the medium.

Communications media typically embody computer-readable instructions,data structures, program modules or other structured or unstructureddata in a data signal such as a modulated data signal, e.g., a carrierwave or other transport mechanism, and comprises any informationdelivery or transport media. The term “modulated data signal” or signalsrefers to a signal that has one or more of its characteristics set orchanged in such a manner as to encode information in one or moresignals. By way of example, and not limitation, communication mediacomprise wired media, such as a wired network or direct-wiredconnection, and wireless media such as acoustic, RF, infrared and otherwireless media.

With reference again to FIG. 4, the example environment can comprise acomputer 402, the computer 402 comprising a processing unit 404, asystem memory 406 and a system bus 408. The system bus 408 couplessystem components including, but not limited to, the system memory 406to the processing unit 404. The processing unit 404 can be any ofvarious commercially available processors. Dual microprocessors andother multiprocessor architectures can also be employed as theprocessing unit 404.

The system bus 408 can be any of several types of bus structure that canfurther interconnect to a memory bus (with or without a memorycontroller), a peripheral bus, and a local bus using any of a variety ofcommercially available bus architectures. The system memory 406comprises ROM 410 and RAM 412. A basic input/output system (BIOS) can bestored in a non-volatile memory such as ROM, erasable programmable readonly memory (EPROM), EEPROM, which BIOS contains the basic routines thathelp to transfer information between elements within the computer 402,such as during startup. The RAM 412 can also comprise a high-speed RAMsuch as static RAM for caching data.

The computer 402 further comprises an internal hard disk drive (HDD) 414(e.g., EIDE, SATA), which internal HDD 414 can also be configured forexternal use in a suitable chassis (not shown), a magnetic floppy diskdrive (FDD) 416, (e.g., to read from or write to a removable diskette418) and an optical disk drive 420, (e.g., reading a CD-ROM disk 422 or,to read from or write to other high capacity optical media such as theDVD). The HDD 414, magnetic FDD 416 and optical disk drive 420 can beconnected to the system bus 408 by a hard disk drive interface 424, amagnetic disk drive interface 426 and an optical drive interface 428,respectively. The hard disk drive interface 424 for external driveimplementations comprises at least one or both of Universal Serial Bus(USB) and Institute of Electrical and Electronics Engineers (IEEE) 1394interface technologies. Other external drive connection technologies arewithin contemplation of the embodiments described herein.

The drives and their associated computer-readable storage media providenonvolatile storage of data, data structures, computer-executableinstructions, and so forth. For the computer 402, the drives and storagemedia accommodate the storage of any data in a suitable digital format.Although the description of computer-readable storage media above refersto a hard disk drive (HDD), a removable magnetic diskette, and aremovable optical media such as a CD or DVD, it should be appreciated bythose skilled in the art that other types of storage media which arereadable by a computer, such as zip drives, magnetic cassettes, flashmemory cards, cartridges, and the like, can also be used in the exampleoperating environment, and further, that any such storage media cancontain computer-executable instructions for performing the methodsdescribed herein.

A number of program modules can be stored in the drives and RAM 412,comprising an operating system 430, one or more application programs432, other program modules 434 and program data 436. All or portions ofthe operating system, applications, modules, and/or data can also becached in the RAM 412. The systems and methods described herein can beimplemented utilizing various commercially available operating systemsor combinations of operating systems.

A user can enter commands and information into the computer 402 throughone or more wired/wireless input devices, e.g., a keyboard 438 and apointing device, such as a mouse 440. Other input devices (not shown)can comprise a microphone, an infrared (IR) remote control, a joystick,a game pad, a stylus pen, touch screen or the like. These and otherinput devices are often connected to the processing unit 404 through aninput device interface 442 that can be coupled to the system bus 408,but can be connected by other interfaces, such as a parallel port, anIEEE 1394 serial port, a game port, a universal serial bus (USB) port,an IR interface, etc.

A monitor 444 or other type of display device can be also connected tothe system bus 408 via an interface, such as a video adapter 446. Itwill also be appreciated that in alternative embodiments, a monitor 444can also be any display device (e.g., another computer having a display,a smart phone, a tablet computer, etc.) for receiving displayinformation associated with computer 402 via any communication means,including via the Internet and cloud-based networks. In addition to themonitor 444, a computer typically comprises other peripheral outputdevices (not shown), such as speakers, printers, etc.

The computer 402 can operate in a networked environment using logicalconnections via wired and/or wireless communications to one or moreremote computers, such as a remote computer(s) 448. The remotecomputer(s) 448 can be a workstation, a server computer, a router, apersonal computer, portable computer, microprocessor-based entertainmentappliance, a peer device or other common network node, and typicallycomprises many or all of the elements described relative to the computer402, although, for purposes of brevity, only a remote memory/storagedevice 450 is illustrated. The logical connections depicted comprisewired/wireless connectivity to a local area network (LAN) 452 and/orlarger networks, e.g., a wide area network (WAN) 454. Such LAN and WANnetworking environments are commonplace in offices and companies, andfacilitate enterprise-wide computer networks, such as intranets, all ofwhich can connect to a global communications network, e.g., theInternet.

When used in a LAN networking environment, the computer 402 can beconnected to the LAN 452 through a wired and/or wireless communicationnetwork interface or adapter 456. The adapter 456 can facilitate wiredor wireless communication to the LAN 452, which can also comprise awireless AP disposed thereon for communicating with the adapter 456.

When used in a WAN networking environment, the computer 402 can comprisea modem 458 or can be connected to a communications server on the WAN454 or has other means for establishing communications over the WAN 454,such as by way of the Internet. The modem 458, which can be internal orexternal and a wired or wireless device, can be connected to the systembus 408 via the input device interface 442. In a networked environment,program modules depicted relative to the computer 402 or portionsthereof, can be stored in the remote memory/storage device 450. It willbe appreciated that the network connections shown are example and othermeans of establishing a communications link between the computers can beused.

The computer 402 can be operable to communicate with any wirelessdevices or entities operatively disposed in wireless communication,e.g., a printer, scanner, desktop and/or portable computer, portabledata assistant, communications satellite, any piece of equipment orlocation associated with a wirelessly detectable tag (e.g., a kiosk,news stand, restroom), and telephone. This can comprise WirelessFidelity (Wi-Fi) and BLUETOOTH® wireless technologies. Thus, thecommunication can be a predefined structure as with a conventionalnetwork or simply an ad hoc communication between at least two devices.

Wi-Fi can allow connection to the Internet from a couch at home, a bedin a hotel room or a conference room at work, without wires. Wi-Fi is awireless technology similar to that used in a cell phone that enablessuch devices, e.g., computers, to send and receive data indoors and out;anywhere within the range of a base station. Wi-Fi networks use radiotechnologies called IEEE 802.11 (a, b, g, n, ac, ag, etc.) to providesecure, reliable, fast wireless connectivity. A Wi-Fi network can beused to connect computers to each other, to the Internet, and to wirednetworks (which can use IEEE 802.3 or Ethernet). Wi-Fi networks operatein the unlicensed 2.4 and 5 GHz radio bands for example or with productsthat contain both bands (dual band), so the networks can providereal-world performance similar to the basic 10BaseT or 100BaseT wiredEthernet networks used in many offices.

Turning now to FIG. 5, an embodiment 500 of a mobile network platform510 is shown that is an example of network elements 150, 152, 154, 156,and/or VNEs 330, 332, 334, etc. For example, platform 510 can facilitatein whole or in part receiving, by a first radio module at a firstlocation, a wireless MIMO signal, to obtain a first received RF signal.The wireless MIMO signal includes information originating at a remoteMIMO transmitter and conveyed via a wireless channel. An envelope of thefirst received RF signal is detected by the first radio module withoutrequiring a local oscillator, to obtain a first detected basebandsignal. The first detected baseband signal is compared to a referencevalue to obtain a first digital signal that is provided to a digitalprocessor. The digital processor also obtains a second digital signalfrom a second radio module receiving the wireless MIMO signal at asecond location and determines an estimate of the informationoriginating at the remote MIMO transmitter according to the first andsecond digital signals. In one or more embodiments, the mobile networkplatform 510 can generate and receive signals transmitted and receivedby base stations or access points such as base station or access point122. Generally, mobile network platform 510 can comprise components,e.g., nodes, gateways, interfaces, servers, or disparate platforms, thatfacilitate both packet-switched (PS) (e.g., internet protocol (IP),frame relay, asynchronous transfer mode (ATM)) and circuit-switched (CS)traffic (e.g., voice and data), as well as control generation fornetworked wireless telecommunication. As a non-limiting example, mobilenetwork platform 510 can be included in telecommunications carriernetworks and can be considered carrier-side components as discussedelsewhere herein. Mobile network platform 510 comprises CS gatewaynode(s) 512 which can interface CS traffic received from legacy networkslike telephony network(s) 540 (e.g., public switched telephone network(PSTN), or public land mobile network (PLMN)) or a signaling system #7(SS7) network 560. CS gateway node(s) 512 can authorize and authenticatetraffic (e.g., voice) arising from such networks. Additionally, CSgateway node(s) 512 can access mobility, or roaming, data generatedthrough SS7 network 560; for instance, mobility data stored in a visitedlocation register (VLR), which can reside in memory 530. Moreover, CSgateway node(s) 512 interfaces CS-based traffic and signaling and PSgateway node(s) 518. As an example, in a 3GPP UMTS network, CS gatewaynode(s) 512 can be realized at least in part in gateway GPRS supportnode(s) (GGSN). It should be appreciated that functionality and specificoperation of CS gateway node(s) 512, PS gateway node(s) 518, and servingnode(s) 516, is provided and dictated by radio technology(ies) utilizedby mobile network platform 510 for telecommunication over a radio accessnetwork 520 with other devices, such as a radiotelephone 575.

In addition to receiving and processing CS-switched traffic andsignaling, PS gateway node(s) 518 can authorize and authenticatePS-based data sessions with served mobile devices. Data sessions cancomprise traffic, or content(s), exchanged with networks external to themobile network platform 510, like wide area network(s) (WANs) 550,enterprise network(s) 570, and service network(s) 580, which can beembodied in local area network(s) (LANs), can also be interfaced withmobile network platform 510 through PS gateway node(s) 518. It is to benoted that WANs 550 and enterprise network(s) 570 can embody, at leastin part, a service network(s) like IP multimedia subsystem (IMS). Basedon radio technology layer(s) available in technology resource(s) orradio access network 520, PS gateway node(s) 518 can generate packetdata protocol contexts when a data session is established; other datastructures that facilitate routing of packetized data also can begenerated. To that end, in an aspect, PS gateway node(s) 518 cancomprise a tunnel interface (e.g., tunnel termination gateway (TTG) in3GPP UMTS network(s) (not shown)) which can facilitate packetizedcommunication with disparate wireless network(s), such as Wi-Finetworks.

In embodiment 500, mobile network platform 510 also comprises servingnode(s) 516 that, based upon available radio technology layer(s) withintechnology resource(s) in the radio access network 520, convey thevarious packetized flows of data streams received through PS gatewaynode(s) 518. It is to be noted that for technology resource(s) that relyprimarily on CS communication, server node(s) can deliver trafficwithout reliance on PS gateway node(s) 518; for example, server node(s)can embody at least in part a mobile switching center. As an example, ina 3GPP UMTS network, serving node(s) 516 can be embodied in serving GPRSsupport node(s) (SGSN).

For radio technologies that exploit packetized communication, server(s)514 in mobile network platform 510 can execute numerous applicationsthat can generate multiple disparate packetized data streams or flows,and manage (e.g., schedule, queue, format . . . ) such flows. Suchapplication(s) can comprise add-on features to standard services (forexample, provisioning, billing, customer support . . . ) provided bymobile network platform 510. Data streams (e.g., content(s) that arepart of a voice call or data session) can be conveyed to PS gatewaynode(s) 518 for authorization/authentication and initiation of a datasession, and to serving node(s) 516 for communication thereafter. Inaddition to application server, server(s) 514 can comprise utilityserver(s), a utility server can comprise a provisioning server, anoperations and maintenance server, a security server that can implementat least in part a certificate authority and firewalls as well as othersecurity mechanisms, and the like. In an aspect, security server(s)secure communication served through mobile network platform 510 toensure network's operation and data integrity in addition toauthorization and authentication procedures that CS gateway node(s) 512and PS gateway node(s) 518 can enact. Moreover, provisioning server(s)can provision services from external network(s) like networks operatedby a disparate service provider; for instance, WAN 550 or GlobalPositioning System (GPS) network(s) (not shown). Provisioning server(s)can also provision coverage through networks associated to mobilenetwork platform 510 (e.g., deployed and operated by the same serviceprovider), such as the distributed antennas networks shown in FIG. 1(s)that enhance wireless service coverage by providing more networkcoverage.

In at least some embodiments, the base station or access RAN 520 may beadapted to include a low-power MIMO radio 582 having an OOK and/or PSKtransmitter, and/or an OOK and/or PSK receiver and/or an OOK and/or PSKtransceiver according to the low-power, low-complexity radios andrelated devices disclosed herein. Likewise, in at least someembodiments, the mobile device 575 may be adapted to include a low-powerMIMO radio 583 having an OOK and/or PSK transmitter, and/or an OOKand/or PSK receiver and/or an OOK and/or PSK transceiver according tothe low-power, low-complexity radios and related devices disclosedherein.

It is to be noted that server(s) 514 can comprise one or more processorsconfigured to confer at least in part the functionality of mobilenetwork platform 510. To that end, the one or more processor can executecode instructions stored in memory 530, for example. It should beappreciated that server(s) 514 can comprise a content manager, whichoperates in substantially the same manner as described hereinbefore.

In example embodiment 500, memory 530 can store information related tooperation of mobile network platform 510. Other operational informationcan comprise provisioning information of mobile devices served throughmobile network platform 510, subscriber databases; applicationintelligence, pricing schemes, e.g., promotional rates, flat-rateprograms, couponing campaigns; technical specification(s) consistentwith telecommunication protocols for operation of disparate radio, orwireless, technology layers; and so forth. Memory 530 can also storeinformation from at least one of telephony network(s) 540, WAN 550, SS7network 560, or enterprise network(s) 570. In an aspect, memory 530 canbe, for example, accessed as part of a data store component or as aremotely connected memory store.

In order to provide a context for the various aspects of the disclosedsubject matter, FIG. 5, and the following discussion, are intended toprovide a brief, general description of a suitable environment in whichthe various aspects of the disclosed subject matter can be implemented.While the subject matter has been described above in the general contextof computer-executable instructions of a computer program that runs on acomputer and/or computers, those skilled in the art will recognize thatthe disclosed subject matter also can be implemented in combination withother program modules. Generally, program modules comprise routines,programs, components, data structures, etc., that perform particulartasks and/or implement particular abstract data types.

Turning now to FIG. 6, an illustrative embodiment of a communicationdevice 600 is shown. The communication device 600 can serve as anillustrative embodiment of devices such as data terminals 114, mobiledevices 124, vehicle 126, display devices 144 or other client devicesfor communication via either communications network 125. For example,computing device 600 can facilitate in whole or in part receiving, by afirst radio module at a first location, a wireless MIMO signal, toobtain a first received RF signal. The wireless MIMO signal includesinformation originating at a remote MIMO transmitter and conveyed via awireless channel. An envelope of the first received RF signal isdetected by the first radio module without requiring a local oscillator,to obtain a first detected baseband signal. The first detected basebandsignal is compared to a reference value to obtain a first digital signalthat is provided to a digital processor. The digital processor alsoobtains a second digital signal from a second radio module receiving thewireless MIMO signal at a second location and determines an estimate ofthe information originating at the remote MIMO transmitter according tothe first and second digital signals.

The communication device 600 can comprise a wireline and/or wirelesstransceiver 602 (herein transceiver 602), a user interface (UI) 604, apower supply 614, a location receiver 616, a motion sensor 618, anorientation sensor 620, and a controller 606 for managing operationsthereof. The transceiver 602 can support short-range or long-rangewireless access technologies such as Bluetooth®, ZigBee®, WiFi, DECT, orcellular communication technologies, just to mention a few (Bluetooth®and ZigBee® are trademarks registered by the Bluetooth® Special InterestGroup and the ZigBee® Alliance, respectively). Cellular technologies caninclude, for example, CDMA-1X, UMTS/HSDPA, GSM/GPRS, TDMA/EDGE, EV/DO,WiMAX, SDR, LTE, as well as other next generation wireless communicationtechnologies as they arise. The transceiver 602 can also be adapted tosupport circuit-switched wireline access technologies (such as PSTN),packet-switched wireline access technologies (such as TCP/IP, VoIP,etc.), and combinations thereof.

The UI 604 can include a depressible or touch-sensitive keypad 608 witha navigation mechanism such as a roller ball, a joystick, a mouse, or anavigation disk for manipulating operations of the communication device600. The keypad 608 can be an integral part of a housing assembly of thecommunication device 600 or an independent device operably coupledthereto by a tethered wireline interface (such as a USB cable) or awireless interface supporting for example Bluetooth®. The keypad 608 canrepresent a numeric keypad commonly used by phones, and/or a QWERTYkeypad with alphanumeric keys. The UI 604 can further include a display610 such as monochrome or color LCD (Liquid Crystal Display), OLED(Organic Light Emitting Diode) or other suitable display technology forconveying images to an end user of the communication device 600. In anembodiment where the display 610 is touch-sensitive, a portion or all ofthe keypad 608 can be presented by way of the display 610 withnavigation features.

The display 610 can use touch screen technology to also serve as a userinterface for detecting user input. As a touch screen display, thecommunication device 600 can be adapted to present a user interfacehaving graphical user interface (GUI) elements that can be selected by auser with a touch of a finger. The display 610 can be equipped withcapacitive, resistive, or other forms of sensing technology to detecthow much surface area of a user's finger has been placed on a portion ofthe touch screen display. This sensing information can be used tocontrol the manipulation of the GUI elements or other functions of theuser interface. The display 610 can be an integral part of the housingassembly of the communication device 600 or an independent devicecommunicatively coupled thereto by a tethered wireline interface (suchas a cable) or a wireless interface.

The UI 604 can also include an audio system 612 that utilizes audiotechnology for conveying low volume audio (such as audio heard inproximity of a human ear) and high-volume audio (such as speakerphonefor hands free operation). The audio system 612 can further include amicrophone for receiving audible signals of an end user. The audiosystem 612 can also be used for voice recognition applications. The UI604 can further include an image sensor 613 such as a charged coupleddevice (CCD) camera for capturing still or moving images.

The power supply 614 can utilize common power management technologiessuch as replaceable and rechargeable batteries, supply regulationtechnologies, and/or charging system technologies for supplying energyto the components of the communication device 600 to facilitatelong-range or short-range portable communications. Alternatively, or incombination, the charging system can utilize external power sources suchas DC power supplied over a physical interface such as a USB port orother suitable tethering technologies.

The location receiver 616 can utilize location technology such as aglobal positioning system (GPS) receiver capable of assisted GPS foridentifying a location of the communication device 600 based on signalsgenerated by a constellation of GPS satellites, which can be used forfacilitating location services such as navigation. The motion sensor 618can utilize motion sensing technology such as an accelerometer, agyroscope, or other suitable motion sensing technology to detect motionof the communication device 600 in three-dimensional space. Theorientation sensor 620 can utilize orientation sensing technology suchas a magnetometer to detect the orientation of the communication device600 (north, south, west, and east, as well as combined orientations indegrees, minutes, or other suitable orientation metrics).

The communication device 600 can use the transceiver 602 to alsodetermine a proximity to a cellular, WiFi, Bluetooth®, or other wirelessaccess points by sensing techniques such as utilizing a received signalstrength indicator (RSSI) and/or signal time of arrival (TOA) or time offlight (TOF) measurements. The controller 606 can utilize computingtechnologies such as a microprocessor, a digital signal processor (DSP),programmable gate arrays, application specific integrated circuits,and/or a video processor with associated storage memory such as Flash,ROM, RAM, SRAM, DRAM or other storage technologies for executingcomputer instructions, controlling, and processing data supplied by theaforementioned components of the communication device 600. In at leastsome embodiments, the transceiver 602 may be adapted to include alow-power MIMO radio 683 having an OOK and/or PSK transmitter, and/or anOOK and/or PSK receiver and/or an OOK and/or PSK transceiver accordingto the low-power, low-complexity radios and related devices disclosedherein.

Other components not shown in FIG. 6 can be used in one or moreembodiments of the subject disclosure. For instance, the communicationdevice 600 can include a slot for adding or removing an identity modulesuch as a Subscriber Identity Module (SIM) card or Universal IntegratedCircuit Card (UICC). SIM or UICC cards can be used for identifyingsubscriber services, executing programs, storing subscriber data, and soon.

Although the example embodiments disclosed herein are directed to MIMOapplications, it is understood that the disclosed techniques may beapplied, without limitation, to other applications. For example, whereasMIMO systems may use multiple transmitters, it is understood that thereceiver systems, devices, and/or techniques disclosed herein may beused to receive and/or otherwise process RF signals from a singletransmitter. Likewise, the receiver systems, devices, and/or techniquesdisclosed herein may be used to receive and/or otherwise process RFsignals from a multiple different transmitters, not necessarily within aMIMO context. It is conceivable that the receiver systems, devices,and/or techniques disclosed herein may be used to process RF signalsreceived from remote transmitters and/or RF signals received from anearby, or even collocated transmitter. The RF signals may be signalsreceived via line of sight and/or signals received by way of one or morereflections, e.g., vial multipath and/or echo return as in a RADARapplication.

The terms “first,” “second,” “third,” and so forth, as used in theclaims, unless otherwise clear by context, is for clarity only and doesnot otherwise indicate or imply any order in time. For instance, “afirst determination,” “a second determination,” and “a thirddetermination,” does not indicate or imply that the first determinationis to be made before the second determination, or vice versa, etc.

In the subject specification, terms such as “store,” “storage,” “datastore,” data storage,” “database,” and substantially any otherinformation storage component relevant to operation and functionality ofa component, refer to “memory components,” or entities embodied in a“memory” or components comprising the memory. It will be appreciatedthat the memory components described herein can be either volatilememory or nonvolatile memory, or can comprise both volatile andnonvolatile memory, by way of illustration, and not limitation, volatilememory, non-volatile memory, disk storage, and memory storage. Further,nonvolatile memory can be included in read only memory (ROM),programmable ROM (PROM), electrically programmable ROM (EPROM),electrically erasable ROM (EEPROM), or flash memory. Volatile memory cancomprise random access memory (RAM), which acts as external cachememory. By way of illustration and not limitation, RAM is available inmany forms such as synchronous RAM (SRAM), dynamic RAM (DRAM),synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhancedSDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM).Additionally, the disclosed memory components of systems or methodsherein are intended to comprise, without being limited to comprising,these and any other suitable types of memory.

Moreover, it will be noted that the disclosed subject matter can bepracticed with other computer system configurations, comprisingsingle-processor or multiprocessor computer systems, mini-computingdevices, mainframe computers, as well as personal computers, hand-heldcomputing devices (e.g., PDA, phone, smartphone, watch, tabletcomputers, netbook computers, etc.), microprocessor-based orprogrammable consumer or industrial electronics, and the like. Theillustrated aspects can also be practiced in distributed computingenvironments where tasks are performed by remote processing devices thatare linked through a communications network; however, some if not allaspects of the subject disclosure can be practiced on stand-alonecomputers. In a distributed computing environment, program modules canbe located in both local and remote memory storage devices.

In one or more embodiments, information regarding use of services can begenerated including services being accessed, media consumption history,user preferences, and so forth. This information can be obtained byvarious methods including user input, detecting types of communications(e.g., video content vs. audio content), analysis of content streams,sampling, and so forth. The generating, obtaining and/or monitoring ofthis information can be responsive to an authorization provided by theuser. In one or more embodiments, an analysis of data can be subject toauthorization from user(s) associated with the data, such as an opt-in,an opt-out, acknowledgement requirements, notifications, selectiveauthorization based on types of data, and so forth.

Some of the embodiments described herein can also employ artificialintelligence (AI) to facilitate automating one or more featuresdescribed herein. The embodiments (e.g., in connection withautomatically identifying acquired cell sites that provide a maximumvalue/benefit after addition to an existing communication network) canemploy various AI-based schemes for carrying out various embodimentsthereof. Moreover, the classifier can be employed to determine a rankingor priority of each cell site of the acquired network. A classifier is afunction that maps an input attribute vector, x=(x1, x2, x3, x4, . . . ,xn), to a confidence that the input belongs to a class, that is,f(x)=confidence (class). Such classification can employ a probabilisticand/or statistical-based analysis (e.g., factoring into the analysisutilities and costs) to determine or infer an action that a user desiresto be automatically performed. A support vector machine (SVM) is anexample of a classifier that can be employed. The SVM operates byfinding a hypersurface in the space of possible inputs, which thehypersurface attempts to split the triggering criteria from thenon-triggering events. Intuitively, this makes the classificationcorrect for testing data that is near, but not identical to trainingdata. Other directed and undirected model classification approachescomprise, e.g., naïve Bayes, Bayesian networks, decision trees, neuralnetworks, fuzzy logic models, and probabilistic classification modelsproviding different patterns of independence can be employed.Classification as used herein also is inclusive of statisticalregression that is utilized to develop models of priority.

As will be readily appreciated, one or more of the embodiments canemploy classifiers that are explicitly trained (e.g., via a generictraining data) as well as implicitly trained (e.g., via observing UEbehavior, operator preferences, historical information, receivingextrinsic information). For example, SVMs can be configured via alearning or training phase within a classifier constructor and featureselection module. Thus, the classifier(s) can be used to automaticallylearn and perform a number of functions, including but not limited todetermining according to predetermined criteria which of the acquiredcell sites will benefit a maximum number of subscribers and/or which ofthe acquired cell sites will add minimum value to the existingcommunication network coverage, etc.

As used in some contexts in this application, in some embodiments, theterms “component,” “system” and the like are intended to refer to, orcomprise, a computer-related entity or an entity related to anoperational apparatus with one or more specific functionalities, whereinthe entity can be either hardware, a combination of hardware andsoftware, software, or software in execution. As an example, a componentmay be, but is not limited to being, a process running on a processor, aprocessor, an object, an executable, a thread of execution,computer-executable instructions, a program, and/or a computer. By wayof illustration and not limitation, both an application running on aserver and the server can be a component. One or more components mayreside within a process and/or thread of execution and a component maybe localized on one computer and/or distributed between two or morecomputers. In addition, these components can execute from variouscomputer readable media having various data structures stored thereon.The components may communicate via local and/or remote processes such asin accordance with a signal having one or more data packets (e.g., datafrom one component interacting with another component in a local system,distributed system, and/or across a network such as the Internet withother systems via the signal). As another example, a component can be anapparatus with specific functionality provided by mechanical partsoperated by electric or electronic circuitry, which is operated by asoftware or firmware application executed by a processor, wherein theprocessor can be internal or external to the apparatus and executes atleast a part of the software or firmware application. As yet anotherexample, a component can be an apparatus that provides specificfunctionality through electronic components without mechanical parts,the electronic components can comprise a processor therein to executesoftware or firmware that confers at least in part the functionality ofthe electronic components. While various components have beenillustrated as separate components, it will be appreciated that multiplecomponents can be implemented as a single component, or a singlecomponent can be implemented as multiple components, without departingfrom example embodiments.

Further, the various embodiments can be implemented as a method,apparatus or article of manufacture using standard programming and/orengineering techniques to produce software, firmware, hardware, or anycombination thereof to control a computer to implement the disclosedsubject matter. The term “article of manufacture” as used herein isintended to encompass a computer program accessible from anycomputer-readable device or computer-readable storage/communicationsmedia. For example, computer readable storage media can include, but arenot limited to, magnetic storage devices (e.g., hard disk, floppy disk,magnetic strips), optical disks (e.g., compact disk (CD), digitalversatile disk (DVD)), smart cards, and flash memory devices (e.g.,card, stick, key drive). Of course, those skilled in the art willrecognize many modifications can be made to this configuration withoutdeparting from the scope or spirit of the various embodiments.

In addition, the words “example” and “exemplary” are used herein to meanserving as an instance or illustration. Any embodiment or designdescribed herein as “example” or “exemplary” is not necessarily to beconstrued as preferred or advantageous over other embodiments ordesigns. Rather, use of the word example or exemplary is intended topresent concepts in a concrete fashion. As used in this application, theterm “or” is intended to mean an inclusive “or” rather than an exclusive“or”. That is, unless specified otherwise or clear from context, “Xemploys A or B” is intended to mean any of the natural inclusivepermutations. That is, if X employs A; X employs B; or X employs both Aand B, then “X employs A or B” is satisfied under any of the foregoinginstances. In addition, the articles “a” and “an” as used in thisapplication and the appended claims should generally be construed tomean “one or more” unless specified otherwise or clear from context tobe directed to a singular form.

Moreover, terms such as “user equipment,” “mobile station,” “mobile,”subscriber station,” “access terminal,” “terminal,” “handset,” “mobiledevice” (and/or terms representing similar terminology) can refer to awireless device utilized by a subscriber or user of a wirelesscommunication service to receive or convey data, control, voice, video,sound, gaming or substantially any data-stream or signaling-stream. Theforegoing terms are utilized interchangeably herein and with referenceto the related drawings.

Furthermore, the terms “user,” “subscriber,” “customer,” “consumer” andthe like are employed interchangeably throughout, unless contextwarrants particular distinctions among the terms. It should beappreciated that such terms can refer to human entities or automatedcomponents supported through artificial intelligence (e.g., a capacityto make inference based, at least, on complex mathematical formalisms),which can provide simulated vision, sound recognition and so forth.

As employed herein, the term “processor” can refer to substantially anycomputing processing unit or device comprising, but not limited tocomprising, single-core processors; single-processors with softwaremultithread execution capability; multi-core processors; multi-coreprocessors with software multithread execution capability; multi-coreprocessors with hardware multithread technology; parallel platforms; andparallel platforms with distributed shared memory. Additionally, aprocessor can refer to an integrated circuit, an application specificintegrated circuit (ASIC), a digital signal processor (DSP), a fieldprogrammable gate array (FPGA), a programmable logic controller (PLC), acomplex programmable logic device (CPLD), a discrete gate or transistorlogic, discrete hardware components or any combination thereof designedto perform the functions described herein. Processors can exploitnano-scale architectures such as, but not limited to, molecular andquantum-dot based transistors, switches and gates, in order to optimizespace usage or enhance performance of user equipment. A processor canalso be implemented as a combination of computing processing units.

As used herein, terms such as “data storage,” data storage,” “database,”and substantially any other information storage component relevant tooperation and functionality of a component, refer to “memorycomponents,” or entities embodied in a “memory” or components comprisingthe memory. It will be appreciated that the memory components orcomputer-readable storage media, described herein can be either volatilememory or nonvolatile memory or can include both volatile andnonvolatile memory.

What has been described above includes mere examples of variousembodiments. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing these examples, but one of ordinary skill in the art canrecognize that many further combinations and permutations of the presentembodiments are possible. Accordingly, the embodiments disclosed and/orclaimed herein are intended to embrace all such alterations,modifications and variations that fall within the spirit and scope ofthe appended claims. Furthermore, to the extent that the term “includes”is used in either the detailed description or the claims, such term isintended to be inclusive in a manner similar to the term “comprising” as“comprising” is interpreted when employed as a transitional word in aclaim.

In addition, a flow diagram may include a “start” and/or “continue”indication. The “start” and “continue” indications reflect that thesteps presented can optionally be incorporated in or otherwise used inconjunction with other routines. In this context, “start” indicates thebeginning of the first step presented and may be preceded by otheractivities not specifically shown. Further, the “continue” indicationreflects that the steps presented may be performed multiple times and/ormay be succeeded by other activities not specifically shown. Further,while a flow diagram indicates a particular ordering of steps, otherorderings are likewise possible provided that the principles ofcausality are maintained.

As may also be used herein, the term(s) “operably coupled to”, “coupledto”, and/or “coupling” includes direct coupling between items and/orindirect coupling between items via one or more intervening items. Suchitems and intervening items include, but are not limited to, junctions,communication paths, components, circuit elements, circuits, functionalblocks, and/or devices. As an example of indirect coupling, a signalconveyed from a first item to a second item may be modified by one ormore intervening items by modifying the form, nature or format ofinformation in a signal, while one or more elements of the informationin the signal are nevertheless conveyed in a manner than can berecognized by the second item. In a further example of indirectcoupling, an action in a first item can cause a reaction on the seconditem, as a result of actions and/or reactions in one or more interveningitems.

Although specific embodiments have been illustrated and describedherein, it should be appreciated that any arrangement which achieves thesame or similar purpose may be substituted for the embodiments describedor shown by the subject disclosure. The subject disclosure is intendedto cover any and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, can be used in the subject disclosure.For instance, one or more features from one or more embodiments can becombined with one or more features of one or more other embodiments. Inone or more embodiments, features that are positively recited can alsobe negatively recited and excluded from the embodiment with or withoutreplacement by another structural and/or functional feature. The stepsor functions described with respect to the embodiments of the subjectdisclosure can be performed in any order. The steps or functionsdescribed with respect to the embodiments of the subject disclosure canbe performed alone or in combination with other steps or functions ofthe subject disclosure, as well as from other embodiments or from othersteps that have not been described in the subject disclosure. Further,more than or less than all of the features described with respect to anembodiment can also be utilized.

What is claimed is:
 1. A system, comprising: a digital pulse generatoradapted to provide a plurality of digital reference pulses synchronouslyaccording to a radio frequency (RF) reference of a master oscillator,wherein a pulse repetition rate of a digital reference pulse of theplurality of digital reference pulses is substantially less than afrequency of the RF reference; and a switch in communication with thedigital pulse generator and adapted to selectively provide a switcheddigital reference pulse of the plurality of digital reference pulses toa plurality of radio modules adapted to operate in a millimeter wavespectrum, wherein the switched digital reference pulse facilitatesgeneration of an error signal at each of a plurality of radio modulesaccording to a difference between a count of cycles of an adjustablelocal oscillator (LO) between successive pulses of the switched digitalreference pulse and a reference value, an adjustable LO being adapted toprovide a corrected LO signal responsive to the error signal, andwherein the corrected LO signal is synchronized to the masteroscillator.
 2. The system of claim 1, wherein the plurality of radiomodules comprises 100 radio modules, each radio module of the pluralityof radio modules being synchronized to the master oscillator.
 3. Thesystem of claim 1, wherein each radio module of the plurality of radiomodules further comprises a modulator in communication with theadjustable LO, and wherein the modulator is adapted to one of modulate,demodulate or both modulate and demodulate a millimeter wave signalbased on the corrected LO signal.
 4. The system of claim 3, wherein eachradio module of the plurality of radio modules further comprises one ofan analog-to-digital converter (ADC), a digital-to-analog converter(DAC), or both an ADC and a DAC coupled between a baseband digitalprocessor and the modulator.
 5. The system of claim 1, furthercomprising a loop filter in communication between an error detector thatprovides the error signal and the adjustable LO, wherein the loop filteroperates upon the error signal to obtain a filtered error signal, andwherein the adjustable LO is adapted to provide the corrected LO signalresponsive to the filtered error signal.
 6. The system of claim 5,wherein the loop filter comprises an integrator adapted to integrate theerror signal to obtain an integrated error signal, the adjustable LObeing adapted to provide the corrected LO signal responsive to theintegrated error signal.
 7. The system of claim 1, wherein each radiomodule of the plurality of radio modules further comprises a frequencymultiplier in communication with the adjustable LO, wherein thefrequency multiplier provides a multiplied corrected LO signalcomprising a multiple of the corrected LO signal operating within themillimeter wave spectrum, and wherein the multiplied corrected LO signalis coherent with another multiplied corrected LO signal of another radiomodule of the plurality of radio modules.
 8. The system of claim 7,wherein each radio module of the plurality of radio modules furthercomprises a controllable phase shifter, an antenna pattern of an antennaarray in communication with the plurality of radio modules beingdirected according to a phase offset imparted by the controllable phaseshifter.
 9. The system of claim 8, wherein each radio module of theplurality of radio modules further comprises a controllable amplitudeadjuster, an antenna pattern of the antenna array being shaped accordingto an amplitude offset imparted by the controllable amplitude adjuster.10. A method, comprising: generating a plurality of digital referencepulses synchronously according to a radio frequency (RF) reference of amaster oscillator, wherein a pulse repetition rate of a digitalreference pulse of the plurality of digital reference pulses issubstantially less than a frequency of the RF reference; selectivelyswitching the plurality of digital reference pulses to obtain aplurality of switched digital reference pulses; and providing theplurality of switched digital reference pulses to a plurality of radiomodules operating within a millimeter wave spectrum the plurality ofdigital reference pulses countable at the plurality of radio moduleaccording to a plurality of controllable local oscillator (LO) outputsignals to obtain a plurality of count values comparable with areference value to obtain a plurality of difference values, theplurality of controllable LOs adjustable according to the plurality ofdifference values to obtain a plurality of corrected LO signalssynchronized to the master oscillator.
 11. The method of claim 10,wherein the plurality of radio modules comprises 100 radio modules, eachradio module of the plurality of radio modules being synchronized to themaster oscillator.
 12. The method of claim 10, further comprisingdemodulating a received millimeter wave signal according to a correctedLO signal of the plurality of corrected LO signals to obtain a basebandsignal.
 13. The method of claim 12, wherein the demodulating furthercomprises down converting the received millimeter wave signal accordingto the corrected LO signal of the plurality of corrected LO signals toobtain a down-converted signal, the demodulating applied to thedown-converted signal.
 14. The method of claim 12, further comprisingconverting the baseband signal to a digital signal via ananalog-to-digital converter (ADC).
 15. The method of claim 10, furthercomprising modulating a corrected LO signal of the plurality ofcorrected LO signals according to baseband information to obtain amodulated signal.
 16. The method of claim 15, wherein the modulatingfurther comprises up converting an intermediate frequency signalaccording to the corrected LO signal of the plurality of corrected LOsignals to obtain an up-converted signal operating within the millimeterwave spectrum.
 17. The method of claim 16, further comprising convertinga digital baseband signal to an analog signal via a digital-to-analogconverter (DAC).
 18. A system, comprising: a digital pulse generatoradapted to provide a plurality of digital reference pulses according toa radio frequency (RF) reference of a master oscillator, wherein a pulserepetition rate of a digital reference pulse of the plurality of digitalreference pulses is substantially less than a frequency of the RFreference; and a switch in communication with the digital pulsegenerator that provides a respective digital reference pulse of theplurality of digital reference pulses to each radio module of aplurality of radio modules that are adapted to operate in a millimeterwave spectrum, the respective digital reference pulse countable at eachradio module of the plurality of radio modules according to a respectivecontrollable local oscillator (LO) output signal to obtain a respectivecount value comparable with a reference value to obtain a difference,each respective controllable LO being adapted to provide a corrected LOsignal responsive to the difference, the corrected LO signal beingcoherent with other radio modules of the plurality of radio modules. 19.The system of claim 18, wherein a dimension of a respective radio moduleis no larger than a maximum dimension of a respective antenna element,such that a size of each radio module is determined according to themaximum dimension of the respective antenna element.
 20. The system ofclaim 18, wherein each radio module of the plurality of radio modulescomprises a respective mixer in communication with the respectivecontrollable LO and a respective millimeter wave antenna, the respectivemixer facilitating one of a modulation, a demodulation, or both.